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All questions of Motion for Class 9 Exam
What is the average velocity of a car that moved 60 km in 3 hours?
- a)60 km/h
- b)20 km/h
- c)30 km/h
- d)10 km/h
Correct answer is option 'B'. Can you explain this answer?
What is the average velocity of a car that moved 60 km in 3 hours?
a)
60 km/h
b)
20 km/h
c)
30 km/h
d)
10 km/h
|
Kamakshi Singh answered |
Calculation of Average Velocity
To calculate the average velocity of a car that moved 60 km in 3 hours, we need to use the formula:
Average Velocity = Total Distance/Total Time
Substituting the given values in the formula, we get:
Average Velocity = 60 km/3 hours
Simplifying this expression, we get:
Average Velocity = 20 km/h
Therefore, the average velocity of the car is 20 km/h.
Explanation
The average velocity of an object is the total distance covered by the object divided by the total time taken to cover that distance. In this case, the car covered a distance of 60 km in a time of 3 hours. Dividing the total distance by the total time gives us the average velocity of the car, which is 20 km/h.
Conclusion
The average velocity of a car that moved 60 km in 3 hours is 20 km/h. It is important to remember that velocity is a vector quantity, which means it has both magnitude and direction. In this case, since no direction is given, we assume that the car travelled in a straight line.
To calculate the average velocity of a car that moved 60 km in 3 hours, we need to use the formula:
Average Velocity = Total Distance/Total Time
Substituting the given values in the formula, we get:
Average Velocity = 60 km/3 hours
Simplifying this expression, we get:
Average Velocity = 20 km/h
Therefore, the average velocity of the car is 20 km/h.
Explanation
The average velocity of an object is the total distance covered by the object divided by the total time taken to cover that distance. In this case, the car covered a distance of 60 km in a time of 3 hours. Dividing the total distance by the total time gives us the average velocity of the car, which is 20 km/h.
Conclusion
The average velocity of a car that moved 60 km in 3 hours is 20 km/h. It is important to remember that velocity is a vector quantity, which means it has both magnitude and direction. In this case, since no direction is given, we assume that the car travelled in a straight line.
The SI unit for speed is- a)km/hour
- b)m/s
- c)cm/min
- d)none of the above
Correct answer is 'B'. Can you explain this answer?
The SI unit for speed is
a)
km/hour
b)
m/s
c)
cm/min
d)
none of the above
|
Shubham Unni answered |
SI unit for speed
The SI unit for speed is meter per second (m/s).
Explanation
Speed is defined as the distance traveled by an object in a given time. It is a scalar quantity and is measured in units of distance per time. The SI unit of distance is meter (m) and the SI unit of time is second (s). Therefore, the SI unit of speed is meter per second (m/s).
For example, if a car travels a distance of 100 meters in 10 seconds, its speed can be calculated as:
Speed = Distance/Time
= 100 meters/10 seconds
= 10 meters per second (m/s)
Therefore, the speed of the car is 10 m/s.
Conclusion
In conclusion, the SI unit for speed is meter per second (m/s). It is important to use the correct units when measuring speed to ensure consistency and accuracy in calculations.
The SI unit for speed is meter per second (m/s).
Explanation
Speed is defined as the distance traveled by an object in a given time. It is a scalar quantity and is measured in units of distance per time. The SI unit of distance is meter (m) and the SI unit of time is second (s). Therefore, the SI unit of speed is meter per second (m/s).
For example, if a car travels a distance of 100 meters in 10 seconds, its speed can be calculated as:
Speed = Distance/Time
= 100 meters/10 seconds
= 10 meters per second (m/s)
Therefore, the speed of the car is 10 m/s.
Conclusion
In conclusion, the SI unit for speed is meter per second (m/s). It is important to use the correct units when measuring speed to ensure consistency and accuracy in calculations.
The SI unit for speed is- a)km/hour
- b)m/s
- c)cm/min
- d)none of the above
Correct answer is option 'B'. Can you explain this answer?
The SI unit for speed is
a)
km/hour
b)
m/s
c)
cm/min
d)
none of the above
|
|
Anita Menon answered |
Speed:- The distance travelled by a body per unit time is called speed.
.: Speed = Distance Travelled/Time taken
or V = s / t
where v = speed
s = distance travelled
& t = time taken
The S.I. Unit of speed is metres per second written as m/sec
It is a scalar quantity.
1 km/ h = ________ m/s
- a)3/50
- b)18/5
- c)50/3
- d)5/18
Correct answer is option 'D'. Can you explain this answer?
1 km/ h = ________ m/s
a)
3/50
b)
18/5
c)
50/3
d)
5/18
|
Amrutha Mukherjee answered |
Conversion of km/h to m/s
To convert km/h to m/s, we need to use the following conversion factor:
1 km/h = 1000 m/3600 s = 5/18 m/s
So, to convert 1 km/h to m/s, we simply multiply it by 5/18.
Solution
Given, 1 km/h = ?
We need to convert it to m/s.
1 km/h × 5/18 = 5/18 m/s
Therefore, the correct option is (d) 5/18.
To convert km/h to m/s, we need to use the following conversion factor:
1 km/h = 1000 m/3600 s = 5/18 m/s
So, to convert 1 km/h to m/s, we simply multiply it by 5/18.
Solution
Given, 1 km/h = ?
We need to convert it to m/s.
1 km/h × 5/18 = 5/18 m/s
Therefore, the correct option is (d) 5/18.
Which of the following is a correct measure of velocity?
- a)30 s
- b)30 m/s
- c)30 South
- d)30 m/s, South
Correct answer is option 'D'. Can you explain this answer?
Which of the following is a correct measure of velocity?
a)
30 s
b)
30 m/s
c)
30 South
d)
30 m/s, South
|
Pooja Shah answered |
Velocity is a vector quantity, which means it has both magnitude and direction. To correctly measure and describe velocity, you need both these components.
Here’s the analysis of the provided options:
-
30 s: This is a measure of time, not velocity.
-
30 m/s: This is a measure of speed, not velocity, because it does not include a direction.
-
30 South: This describes a direction but lacks the magnitude (speed), so it is not a complete measure of velocity.
-
30 m/s, South: This provides both magnitude (30 m/s) and direction (South), making it a complete measure of velocity.
So, the correct measure of velocity is:
4. 30 m/s, South
How far will a car travel in 25 min at 12 m/s?
- a)24 km
- b)10 km
- c)18 km
- d)14 km
Correct answer is option 'C'. Can you explain this answer?
How far will a car travel in 25 min at 12 m/s?
a)
24 km
b)
10 km
c)
18 km
d)
14 km
|
Molik answered |
S=d/t. .......... t=25min=1500sec. and speed =12m/s.........d=s×t. ...........d=12×1500=18000m. as we hv to convert it into km so 1km=1000m and 1m =1/1000 km so , 18000m=18000/1000km=18km
Speed of 90 km/h when expressed in m/s is- a)2.5
- b)90000
- c)250
- d)25
Correct answer is option 'D'. Can you explain this answer?
Speed of 90 km/h when expressed in m/s is
a)
2.5
b)
90000
c)
250
d)
25
|
Saurabh Kumar answered |
Because when we convert km/h into m/s we multiply 5/18 into km/h so we get m/s according to question we we multiply 5/18 into 90 km/h so90*5/18 = 25SO THE ANSWER IS 25.
Can you explain the answer of this question below:The speed at any instant of time is known as
- A:
velocity
- B:
given speed
- C:
average speed
- D:
instantaneous speed
The answer is d.
The speed at any instant of time is known as
velocity
given speed
average speed
instantaneous speed
|
Gunjan Lakhani answered |
The instantaneous speed of an object is defined as the speed of the object at any given instant. The instantaneous speed of an object can be determined by determining the average speed over a short distance (and short time), and using this approximation as the instantaneous speed.
Topic in NCERT: Motion and Acceleration
Line in NCERT: error Occcured while getting response from embedding
On a velocity-time graph, a horizontal straight line corresponds to motion at- a)constant velocity
- b)zero velocity
- c)increasing velocity
- d)decreasing velocity
Correct answer is option 'A'. Can you explain this answer?
On a velocity-time graph, a horizontal straight line corresponds to motion at
a)
constant velocity
b)
zero velocity
c)
increasing velocity
d)
decreasing velocity
|
|
Arun Sharma answered |
It is horizontal so, angle is zero and also acceleration is zero. Hence constant velocity.
An external influence which changes or tends to change the state of rest or uniform motion of body or its dimensions is called:- a)momentum
- b)force
- c)moment of force
- d)pressure
Correct answer is 'B'. Can you explain this answer?
An external influence which changes or tends to change the state of rest or uniform motion of body or its dimensions is called:
a)
momentum
b)
force
c)
moment of force
d)
pressure
|
|
Ananya Das answered |
The slope of the velocity-time graph determines the acceleration.
Can you explain the answer of this question below:An athlete uniformly increases his speed from rest at the rate of 1 m/s2. The time taken to complete 200 m race is:
- A:
10 s
- B:
14 s
- C:
5 s
- D:
20 s
The answer is d.
An athlete uniformly increases his speed from rest at the rate of 1 m/s2. The time taken to complete 200 m race is:
10 s
14 s
5 s
20 s
|
Ashish Saha answered |
v= 80*1000/3600 = 22.22 u=20*1000/3600=5.55 , Now a = v-u/t = 22.22-5.55/2 = 8.335
Can you explain the answer of this question below:An object travels 20 m in 5 sec and then another 40 m in 5 sec. What is the average speed of the object?
- A:
6 m/s
- B:
2 m/s
- C:
12 m/s
- D:
0 m/s
The answer is a.
An object travels 20 m in 5 sec and then another 40 m in 5 sec. What is the average speed of the object?
6 m/s
2 m/s
12 m/s
0 m/s
|
Learning Education answered |
Average speed= (Total Distance)/(Total time)
= (20 m + 40 m)/(5 sec + 5 sec)
=60 m/10 sec
=6m/s
Name the instrument used to measure instantaneous speed of a vehicle- a)multimeter
- b)ammeter
- c)speedometer
- d)accelerator
Correct answer is option 'C'. Can you explain this answer?
Name the instrument used to measure instantaneous speed of a vehicle
a)
multimeter
b)
ammeter
c)
speedometer
d)
accelerator
|
|
Anita Menon answered |
The speedometer device is used to measure speed. A speedometer is also called a speedometer, it is a gauge that measures and displays the instantaneous speed of a vehicle.
The area under the speed-time graph gives the ________.- a)velocity
- b)distance
- c)acceleration
- d)time
Correct answer is 'B'. Can you explain this answer?
The area under the speed-time graph gives the ________.
a)
velocity
b)
distance
c)
acceleration
d)
time
|
Trisha Vashisht answered |
Area under the speed-time graph gives the distance:
- When calculating the area under a speed-time graph, you are essentially finding the total distance traveled by an object over a certain period of time.
- This is because the area under a speed-time graph represents the total distance covered by an object as it moves at varying speeds.
- By finding the area under the curve on a speed-time graph, you can determine the total distance traveled by the object during that time interval.
Can you explain the answer of this question below:If a person walked at 2 m/s for 12 s he/she would travel a distance of
- A:
24 m
- B:
6 m
- C:
4 m
- D:
none of the answers
The answer is a.
If a person walked at 2 m/s for 12 s he/she would travel a distance of
24 m
6 m
4 m
none of the answers
|
Piyush Srivastava answered |
1second =2meter 12 second = 12*2meter 24metet
If car A is at 40 km/h and car B is at 10 km/h in the opposite direction, what is the velocity of the car A relative to the car B?
- a)40 km/h
- b)50 km/h.
- c)10 km/h
- d)30 km/h
Correct answer is option 'B'. Can you explain this answer?
If car A is at 40 km/h and car B is at 10 km/h in the opposite direction, what is the velocity of the car A relative to the car B?
a)
40 km/h
b)
50 km/h.
c)
10 km/h
d)
30 km/h
|
Hiral Datta answered |
Taking the formula when both bodies are moving along opposite direction we have :
V(AB) = V(A) - V(B) = 40 - (-10 ) = 50 km/hr
Hence the velocity of car A with respect to car B is 50 km/hr in opposite direction.
Find the average speed of a bicycle if it completes two round of a circular track of radius 140m twice in 5min 52 sec.- a)10m/s
- b)5m/s
- c)2m/s
- d)4m/s
Correct answer is option 'B'. Can you explain this answer?
Find the average speed of a bicycle if it completes two round of a circular track of radius 140m twice in 5min 52 sec.
a)
10m/s
b)
5m/s
c)
2m/s
d)
4m/s
|
|
Rohit Sharma answered |
Radius of truck = r = 140m
circumfarance
Time taken to cover the distance = t = 5 min 52 sec = 352 sec
Since it complete 2 rounds, therefor distance it travels is 2 times of circumference.
circumfarance
Time taken to cover the distance = t = 5 min 52 sec = 352 sec
Since it complete 2 rounds, therefor distance it travels is 2 times of circumference.
In a distance-time graph, if the line is horizontal, then the object is:- a)Accelerating
- b)Speeding up
- c)At rest
- d)Slowing down
Correct answer is option 'C'. Can you explain this answer?
In a distance-time graph, if the line is horizontal, then the object is:
a)
Accelerating
b)
Speeding up
c)
At rest
d)
Slowing down
|
Destroyed answered |
When an object is at rest it will not be able to cover any distance . So for any object at rest the distance -time graph is horizontal to time axis
Can you explain the answer of this question below:A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:- A:19 m
- B:17 m
- C:16 m
- D:18 m
The answer is a.
A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:
A:
19 m
B:
17 m
C:
16 m
D:
18 m
|
Sarita Reddy answered |
Given :
u = 36 km/h = 36x (5/18) = 10 m/s
Time of reaction, t = 0.9 s
decelration, a = -5 m/s^2
v = 0 m/s
Let s1 be the distance covered by man when the object is seen by him
we have, u = s1/t
because s1 = u x t
= 10 x 0.9
= 9 m
when he applies brakes and decelerates at the rate of 5 m/s^2, the distance covered by him is s2
We have, v^2 = u^2 + 2as2
therefore 0 = u^2 - 2as2 ( therefore v=0 m/s)
therefore s2 = u^2/2a = 10^2/ (2 x 5)
therefore s2 =10 m
So, total distance covered s = s1 + s2 = 9 +10 =19 m
Hence 19 m distance covered by man before he stops.
Equations of motion can be used for a body having- a)uniform motion
- b)non-uniform motion
- c)uniform acceleration
- d)non-uniform acceleration
Correct answer is option 'C'. Can you explain this answer?
Equations of motion can be used for a body having
a)
uniform motion
b)
non-uniform motion
c)
uniform acceleration
d)
non-uniform acceleration
|
|
Ananya Das answered |
The equations of motion are applicable only when the body moves with uniform acceleration. A body under constant acceleration is uniformly accelerated motion.
The area enclosed by velocity-time graph and the time axis will be equal to the magnitude of- a)displacement
- b)speed
- c)acceleration
- d)distance
Correct answer is option 'A'. Can you explain this answer?
The area enclosed by velocity-time graph and the time axis will be equal to the magnitude of
a)
displacement
b)
speed
c)
acceleration
d)
distance
|
Ishaan Chauhan answered |
Explanation:
Derivation:
Conclusion:
When an object is in motion, its velocity changes with time. The velocity-time graph shows the variation of velocity with time. The area enclosed by the velocity-time graph and the time axis represents the distance travelled by the object in a given time interval.
Derivation:
Let's consider an object moving with a variable velocity v(t) in a straight line. The velocity of the object at any instant t is given by:
v(t) = ds/dt
where s is the displacement of the object at time t. Integrating both sides, we get:
s = ∫v(t) dt
The integral of velocity with respect to time gives the displacement of the object. The area under the velocity-time graph represents the area of the region bounded by the graph, the time axis and the two vertical lines drawn at the beginning and end of the time interval.
Conclusion:
Therefore, the area enclosed by the velocity-time graph and the time axis represents the displacement of the object. Hence, option 'A' is the correct answer.
The slope of the distance-time graph is:- a)Distance
- b)acceleration
- c)Speed
- d)Displacement
Correct answer is option 'C'. Can you explain this answer?
The slope of the distance-time graph is:
a)
Distance
b)
acceleration
c)
Speed
d)
Displacement
|
|
Sarita Reddy answered |
The gradient of a distance-time graph represents the speed of an object. The velocity of an object is its speed in a particular direction. The slope on a velocity-time graph represents the acceleration of an object. The distance travelled is equal to the area under a velocity-time graph.
Which of the following graphs show that the body is at rest?- a)
- b)
- c)
- d)
Correct answer is option 'A'. Can you explain this answer?
Which of the following graphs show that the body is at rest?
a)
b)
c)
d)
|
Ishan Choudhury answered |
In figure A, we can see that the object continues to remain at a fixed place while the time keeps running. So, the object is at rest, because the object does not change its position with time.
Odometer of automobiles records
- a)average speed
- b)instantaneous speed
- c)distance travelled
- d)acceleration
Correct answer is option 'C'. Can you explain this answer?
Odometer of automobiles records
a)
average speed
b)
instantaneous speed
c)
distance travelled
d)
acceleration
|
Imk Pathshala answered |
- Odometer of automobiles records distance travelled.
- The primary function of an odometer in automobiles is to measure and display the total distance the vehicle has traveled since it was first put into use.
- This distance is usually displayed in kilometers or miles depending on the unit system used in the region.
Topic in NCERT: Example 7.2
Line in NCERT: "The odometer of a car reads 2000 km at the start of a trip and 2400 km at the end of the trip."
How long would it take to travel 50 km traveling at a speed of 10 km/hr?- a)5 hours
- b)1 hour
- c)3 hours
- d)50 hours
Correct answer is option 'A'. Can you explain this answer?
How long would it take to travel 50 km traveling at a speed of 10 km/hr?
a)
5 hours
b)
1 hour
c)
3 hours
d)
50 hours
|
|
Bhaskar Chatterjee answered |
Given data:
Distance = 50 km
Speed = 10 km/hr
To find: Time taken to travel 50 km
Calculation:
We know that,
Speed = Distance/Time
⇒ Time = Distance/Speed
Substituting the given values, we get
Time = 50/10
Time = 5 hours
Therefore, the time taken to travel 50 km at a speed of 10 km/hr is 5 hours.
Answer: (a) 5 hours
Distance = 50 km
Speed = 10 km/hr
To find: Time taken to travel 50 km
Calculation:
We know that,
Speed = Distance/Time
⇒ Time = Distance/Speed
Substituting the given values, we get
Time = 50/10
Time = 5 hours
Therefore, the time taken to travel 50 km at a speed of 10 km/hr is 5 hours.
Answer: (a) 5 hours
A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:- a)19 m
- b)17 m
- c)16 m
- d)18 m
Correct answer is 'A'. Can you explain this answer?
A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:
a)
19 m
b)
17 m
c)
16 m
d)
18 m
|
|
Arvind Singh answered |
Given . u = 36 km/h=36x (5/18)=10 m/s Time of reaction, t=0.9 s decelration, a=-5 m/s^2 v = 0 m/s Let s1 be the distance covered by man when the object is seen by him we have, u = s1/t because s1 = u x t=10x0.9 =9 m when he applies brakes and decelerates at the rate of 5 m/s^2, the distance covered by him is s2 We have, v^2 = u^2 + 2as2 because 0 = u^2 - 2as2 (because v=0 m/s) because s2 = u^2/2a = 10^2/2x5 s2 =10 m So, total distance covered s = s1 + s2 = 9 + 10 =19 m Hence 19 m distance covered by man before he stops.
For a body performing motion with uniform speed, the distance-time graph is:- a)Straight line parallel to y-axis
- b)Straight line inclined to the time axis
- c)Straight line parallel to x-axis
- d)Curved line
Correct answer is 'B'. Can you explain this answer?
For a body performing motion with uniform speed, the distance-time graph is:
a)
Straight line parallel to y-axis
b)
Straight line inclined to the time axis
c)
Straight line parallel to x-axis
d)
Curved line
|
|
Rohit Sharma answered |
For a body moving at uniform speed, the distance time graph is a straight line inclined to the time axis, which may pass through origin or some other point on the y- axis.
As in uniform motion, the distance time graph would be a straight line, because the equal distance is covered in equal units of time.
As in uniform motion, the distance time graph would be a straight line, because the equal distance is covered in equal units of time.
Suppose a boy is enjoying a ride on a merry go round which is moving with a constant speed of 10 ms-1. It implies that the boy is
- a)at rest
- b)moving with no acceleration
- c)in accelerated motion
- d)moving with unifoim velocity
Correct answer is option 'C'. Can you explain this answer?
Suppose a boy is enjoying a ride on a merry go round which is moving with a constant speed of 10 ms-1. It implies that the boy is
a)
at rest
b)
moving with no acceleration
c)
in accelerated motion
d)
moving with unifoim velocity
|
Gaurav Kumar answered |
- Acceleration is the measure of how fast the velocity changes.
- Velocity is a vector quantity and a change in velocity is due to change in magnitude or change in direction or both.
- Here, the boy is moving with constant speed but velocity changes and hence is supposed to be in accelerated motion.
A vector quantity has- a)direction
- b)magnitude
- c)both magnitude and direction
- d)none of these
Correct answer is option 'C'. Can you explain this answer?
A vector quantity has
a)
direction
b)
magnitude
c)
both magnitude and direction
d)
none of these
|
EduRev Class 9 answered |
Vector Quantity
- Direction: A vector quantity has a specific direction in space. This means that not only does it have a magnitude, but it also has a specific orientation or direction in which it is pointing.
- Magnitude: In addition to having a direction, a vector quantity also has a magnitude. This magnitude represents the size or strength of the vector, indicating how much of the quantity is present.
- Both Magnitude and Direction: Therefore, a vector quantity possesses both magnitude and direction, distinguishing it from scalar quantities which only have magnitude. This dual nature of vectors allows for a more detailed description of physical quantities.
A body performs an accelerated motion, with uniform speed. The motion of body is- a)Linear
- b)Circular
- c)Parabolic
- d)Irregular
Correct answer is 'B'. Can you explain this answer?
A body performs an accelerated motion, with uniform speed. The motion of body is
a)
Linear
b)
Circular
c)
Parabolic
d)
Irregular
|
Shounak Chauhan answered |
Explanation:
When a body performs an accelerated motion with uniform speed, its motion is circular. The reason behind it can be explained in the following points:
Uniform Speed:
Uniform speed means the body is moving with a constant speed. It means that the magnitude of the velocity of the body is constant. The direction of the velocity vector can be changed, but the magnitude of the velocity remains constant.
Accelerated Motion:
Accelerated motion means the velocity of the body is changing with time. It means that the magnitude of the acceleration of the body is not zero. The direction of the acceleration vector can be changed, but the magnitude of the acceleration is not zero.
Circular Motion:
Circular motion is a kind of motion in which a body moves in a circular path. In circular motion, the direction of the velocity vector changes continuously, but the magnitude of the velocity remains constant. The direction of the acceleration vector also changes continuously, but the magnitude of the acceleration is not zero.
Conclusion:
When a body performs an accelerated motion with uniform speed, its motion is circular. In this case, the magnitude of the velocity of the body remains constant, but the direction of the velocity vector changes continuously. The magnitude of the acceleration of the body is not zero, and the direction of the acceleration vector also changes continuously. Hence, the motion of the body is circular.
When a body performs an accelerated motion with uniform speed, its motion is circular. The reason behind it can be explained in the following points:
Uniform Speed:
Uniform speed means the body is moving with a constant speed. It means that the magnitude of the velocity of the body is constant. The direction of the velocity vector can be changed, but the magnitude of the velocity remains constant.
Accelerated Motion:
Accelerated motion means the velocity of the body is changing with time. It means that the magnitude of the acceleration of the body is not zero. The direction of the acceleration vector can be changed, but the magnitude of the acceleration is not zero.
Circular Motion:
Circular motion is a kind of motion in which a body moves in a circular path. In circular motion, the direction of the velocity vector changes continuously, but the magnitude of the velocity remains constant. The direction of the acceleration vector also changes continuously, but the magnitude of the acceleration is not zero.
Conclusion:
When a body performs an accelerated motion with uniform speed, its motion is circular. In this case, the magnitude of the velocity of the body remains constant, but the direction of the velocity vector changes continuously. The magnitude of the acceleration of the body is not zero, and the direction of the acceleration vector also changes continuously. Hence, the motion of the body is circular.
A body starts to slide over a horizontal surface with an initial velocity of 0.2 m/s. Due to friction, its velocity decreases at the rate of 0.02 m/s2. How much time will it take for the body to stop?- a)10 s
- b)15s
- c)1s
- d)5s
Correct answer is option 'A'. Can you explain this answer?
A body starts to slide over a horizontal surface with an initial velocity of 0.2 m/s. Due to friction, its velocity decreases at the rate of 0.02 m/s2. How much time will it take for the body to stop?
a)
10 s
b)
15s
c)
1s
d)
5s
|
|
Anita Menon answered |
Initial velocity, u = 0.2 m/s.
Final velocity, v = 0
Acceleration, a = 0.02 m/s^2.
v = u + at
0 = 0.2 - 0.02 x t
0.02 x t = 0.2
t = 0.2/0.02 = 10 sec.
Thus, the body will take 10 seconds to stop.
Can you explain the answer of this question below:The ______ of a distance versus time graph is speed.
- A:
slope
- B:
y-intercept
- C:
origin
- D:
none of the answers
The answer is a.
The ______ of a distance versus time graph is speed.
slope
y-intercept
origin
none of the answers
|
|
Raghav Chatterjee answered |
The Relationship between Distance and Time
When an object moves, it covers a certain distance in a certain amount of time. The relationship between distance and time can be represented on a graph called a distance-time graph.
The Slope of a Distance-Time Graph
The slope of a distance-time graph represents the speed of the object. The slope is defined as the change in distance divided by the change in time. Mathematically, the slope can be written as:
Slope = Change in distance / Change in time
In other words, the slope of the graph gives us the rate at which the distance is changing with respect to time. This rate is the speed of the object.
Interpretation of the Slope
If the slope of the graph is steep, it means that the object is covering a large distance in a short amount of time. This indicates that the object is moving at a high speed.
If the slope of the graph is shallow, it means that the object is covering a small distance in a long amount of time. This indicates that the object is moving at a low speed.
Conclusion
Therefore, the correct answer to the given question is option 'A' - the slope of a distance versus time graph is speed. The slope of a distance-time graph gives us the speed of the object.
When an object moves, it covers a certain distance in a certain amount of time. The relationship between distance and time can be represented on a graph called a distance-time graph.
The Slope of a Distance-Time Graph
The slope of a distance-time graph represents the speed of the object. The slope is defined as the change in distance divided by the change in time. Mathematically, the slope can be written as:
Slope = Change in distance / Change in time
In other words, the slope of the graph gives us the rate at which the distance is changing with respect to time. This rate is the speed of the object.
Interpretation of the Slope
If the slope of the graph is steep, it means that the object is covering a large distance in a short amount of time. This indicates that the object is moving at a high speed.
If the slope of the graph is shallow, it means that the object is covering a small distance in a long amount of time. This indicates that the object is moving at a low speed.
Conclusion
Therefore, the correct answer to the given question is option 'A' - the slope of a distance versus time graph is speed. The slope of a distance-time graph gives us the speed of the object.
Distance covered by a body from velocity-time graph is- a)Equal to the slope of the graph.
- b)Area under the graph .
- c)Is denoted by a line parallel to the time axis at any point on the distance axis.
- d)Is denoted by a line parallel to the distance axis at any point on the time axis
Correct answer is option 'B'. Can you explain this answer?
Distance covered by a body from velocity-time graph is
a)
Equal to the slope of the graph.
b)
Area under the graph .
c)
Is denoted by a line parallel to the time axis at any point on the distance axis.
d)
Is denoted by a line parallel to the distance axis at any point on the time axis
|
|
Ravi Verma answered |
The area under the line in a velocity-time graph represents the distance travelled. To find the distance travelled in the graph above, you need to find the area of the light-blue triangle and the dark-blue rectangle. The width of the rectangle is 6 seconds and the height is 8 metres per second.
Match the following with correct response. 
- a)1-B, 2-D, 3-A, 4-C
- b)1-D, 2-A, 3-C, 4-B
- c)1-C, 2-B, 3-D, 4-A
- d)1-A, 2-C, 3-B, 4-D
Correct answer is option 'B'. Can you explain this answer?
Match the following with correct response.
a)
1-B, 2-D, 3-A, 4-C
b)
1-D, 2-A, 3-C, 4-B
c)
1-C, 2-B, 3-D, 4-A
d)
1-A, 2-C, 3-B, 4-D
|
BT Educators answered |
The correct option is B.
For a body moving at a uniform velocity you can calculate the speed by dividing the distance traveled by the amount of time it took, for example one mile in 1/2 hour would give you 2 miles per hour.
In order to find the velocity of the moving object, you will need to divide the change in position by the change in time. Specify the direction moved, and you have the average velocity.
Calculating acceleration involves dividing velocity by time — or in terms of SI units, dividing the meter per second [m/s] by the second [s]. Dividing distance by time twice is the same as dividing distance by the square of time. Thus the SI unit of acceleration is the meter per second squared
Average speed is calculated by dividing distance by time (e.g. miles/hour). Okay we're going to talk about average speed, instantaneous speed is the distance that you're covering at a specific time. So 100 kilometers an hour, average speed is the total distance you're going to cover over a period of time.
For a body moving at a uniform velocity you can calculate the speed by dividing the distance traveled by the amount of time it took, for example one mile in 1/2 hour would give you 2 miles per hour.
In order to find the velocity of the moving object, you will need to divide the change in position by the change in time. Specify the direction moved, and you have the average velocity.
Calculating acceleration involves dividing velocity by time — or in terms of SI units, dividing the meter per second [m/s] by the second [s]. Dividing distance by time twice is the same as dividing distance by the square of time. Thus the SI unit of acceleration is the meter per second squared
Average speed is calculated by dividing distance by time (e.g. miles/hour). Okay we're going to talk about average speed, instantaneous speed is the distance that you're covering at a specific time. So 100 kilometers an hour, average speed is the total distance you're going to cover over a period of time.
- a)19 m
- b)17 m
- c)16 m
- d)18 m
Correct answer is 'A'. Can you explain this answer?
|
|
Anita Menon answered |
Given :
u = 36 km/h = 36x (5/18) =10 m/s
Time of reaction, t = 0.9 s
decelration, a = -5 m/s^2
v = 0 m/s
Let sl be the distance covered by man when the object is seen by him
we have, u = s1/t
therefore s1 = u x t
= 10 x 0.9
= 9 m
when he applies brakes and decelerates at the rate of 5 m/s2, the distance covered by him is s2
We have, v^2 = u^2 + 2as2
therefore 0 = u^2 - 2as2 (because v=0 m/s)
therefore s2 = u^2/2a = 10^2/2 x 5
therefore s2 = 10 m
So, total distance covered s = s1+ s2 = 9 +10 =19 m
Hence 19 m distance covered by man before he stops.
Can you explain the answer of this question below:The equations of motion can be derived by using:
- A:
Distance – time graph
- B:
Velocity – time graph for non-uniform acceleration
- C:
Displacement time graph
- D:
Velocity – time graph for uniform acceleration
The answer is d.
The equations of motion can be derived by using:
Distance – time graph
Velocity – time graph for non-uniform acceleration
Displacement time graph
Velocity – time graph for uniform acceleration
|
|
Niharika Kapoor answered |
B)Velocity
c)Acceleration
d)Time
c)Acceleration
d)Time
A body starting at a point, say A, reaches, say B, ahead in a straight line and returns back to A. Then there is
- a)positive displacement
- b)negative displacement
- c)zero displacement
- d)cannot be said
Correct answer is option 'C'. Can you explain this answer?
A body starting at a point, say A, reaches, say B, ahead in a straight line and returns back to A. Then there is
a)
positive displacement
b)
negative displacement
c)
zero displacement
d)
cannot be said
|
|
Imk Pathshala answered |
- Displacement is the straight line distance between the starting and ending points of an object's motion.
- In this scenario, the body starts at A, goes to B, and then returns to A. Even though the body travels a certain distance (twice the distance between A and B), it ends up back at its starting point (A).
- Since displacement considers the net change in position, and the body ends at the same point it started, the displacement is zero.
Topic in NCERT: Motion Along a Straight Line
Line in NCERT: "the final position coincides with the initial position, and therefore, the displacement is zero."
The numerical ratio of displacement to distance for a moving object is
- a)always less than 1
- b)always equal to 1
- c)always more than 1
- d)equal to or less than 1
Correct answer is option 'D'. Can you explain this answer?
The numerical ratio of displacement to distance for a moving object is
a)
always less than 1
b)
always equal to 1
c)
always more than 1
d)
equal to or less than 1
|
Let's Tute answered |
- Displacement is the straightest shot (shortest distance) between start and end.
- Distance is the total path taken.
- Imagine going for a walk around a block - the displacement is the length of one side, while the distance is the entire walk.
- The numerical ratio of displacement to distance is calculated as displacement divided by distance.
- So the ratio:
- Can be 1 (straight path)
- Is less than 1 (curved path or going back and forth)
- Never more than 1
Therefore, the answer is D: equal to or less than 1.
Topic in NCERT: MOTION ALONG A STRAIGHT LINE
Line in NCERT: "The magnitude of displacement (35 km) is not equal to the path length (85 km)."
The displacement of the body in 5 seconds from the beginning of the motion is
- a)12.5 m
- b)100 m
- c)87.5 m
- d)50 m
Correct answer is option 'D'. Can you explain this answer?
The displacement of the body in 5 seconds from the beginning of the motion is
a)
12.5 m
b)
100 m
c)
87.5 m
d)
50 m
|
|
Trisha Vashisht answered |
Displacement = Area under the velocity- time graph the slope till 5 cm
the slope is a straight line and thus its area will be equal to the area of the triangle with height = 20 and base = 5
the slope is a straight line and thus its area will be equal to the area of the triangle with height = 20 and base = 5
Area of triangle = 1/2 x base x height
Area = 1/2 x 5 x 20 = 50 m.
What is the slope of distance-time graph when object is at rest?- a)Decreases continuously
- b)Zero
- c)Increases continuously
- d)One
Correct answer is option 'B'. Can you explain this answer?
What is the slope of distance-time graph when object is at rest?
a)
Decreases continuously
b)
Zero
c)
Increases continuously
d)
One
|
Preetam Pyare answered |
Since The Body is at Rest ,It clearly means that The Body hasn't covered any Distance here.So,Distance is equal to zero.So,There is no meaning of having any slope here.. So,The Slope=0 Becoz The Distance at anytime will represent same point in Distance-Time Graph at 0..So,(B)is d correct answer. .
A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:- a)19 m
- b)17 m
- c)16 m
- d)18 m
Correct answer is option 'A'. Can you explain this answer?
A man is moving with 36 kmph. The time of reaction is 0.9 seconds. On seeing an obstacle in the path, he applies brakes and decelerates at 5 m/s2, the total distance covered before he stops is:
a)
19 m
b)
17 m
c)
16 m
d)
18 m
|
|
Ananya Sharma answered |
Given :
u = 36 km/h = 36x (5/18) = 10 m/s
Time of reaction, t = 0.9 s
decelration, a = -5 m/s^2
v = 0 m/s
Let s1 be the distance covered by man when the object is seen by him
we have, u = s1/t
because s1 = u x t
= 10 x 0.9
= 9 m
when he applies brakes and decelerates at the rate of 5 m/s^2, the distance covered by him is s2
We have, v^2 = u^2 + 2as2
therefore 0 = u^2 - 2as2 ( therefore v=0 m/s)
therefore s2 = u^2/2a = 10^2/ (2 x 5)
therefore s2 =10 m
So, total distance covered s = s1 + s2 = 9 +10 =19 m
Hence 19 m distance covered by man before he stops.
An external influence which changes or tends to change the state of rest or uniform motion of body or its dimensions is called:- a)momentum
- b)force
- c)moment of force
- d)pressure
Correct answer is option 'B'. Can you explain this answer?
An external influence which changes or tends to change the state of rest or uniform motion of body or its dimensions is called:
a)
momentum
b)
force
c)
moment of force
d)
pressure
|
|
Ananya Das answered |
The slope of the velocity-time graph determines the acceleration.
The speed-time graph for a particle moving at constant speed is a straight-line ________ to the time axis.- a)perpendicular
- b)parallel
- c)inclined
- d)aligned
Correct answer is option 'B'. Can you explain this answer?
The speed-time graph for a particle moving at constant speed is a straight-line ________ to the time axis.
a)
perpendicular
b)
parallel
c)
inclined
d)
aligned
|
|
Ananya Sharma answered |
The speed-time graph for a particle moving at constant speed is a straight-line parallel to the time axis.
The speedometer of a car measures
- a)average speed
- b)instantaneous speed
- c)acceleration
- d)none of the
Correct answer is option 'B'. Can you explain this answer?
The speedometer of a car measures
a)
average speed
b)
instantaneous speed
c)
acceleration
d)
none of the
|
|
Let's Tute answered |
Speedometer Measurement
- Instantaneous Speed: The speedometer of a car measures the instantaneous speed at any given moment.
- It provides a real-time reading of how fast the car is moving at that particular moment.
- This measurement is important for drivers to ensure they are following speed limits and driving safely.
- It helps drivers make adjustments to their speed based on road conditions, traffic, and other factors.
If the displacement-time graph of a particle is parallel to the time axis, the velocity of the particle is
- a)unity
- b)infinity
- c)zero
- d)none of these
Correct answer is option 'C'. Can you explain this answer?
If the displacement-time graph of a particle is parallel to the time axis, the velocity of the particle is
a)
unity
b)
infinity
c)
zero
d)
none of these
|
|
Imk Pathshala answered |
- If the displacement-time graph of a particle is parallel to the time axis, this means that the displacement remains constant over time. In other words, there is no change in displacement as time progresses.
- Since velocity is defined as the rate of change of displacement with respect to time, and there is no change in displacement, the velocity of the particle is zero.
Topic in NCERT: VELOCITY-TIME GRAPHS
Line in NCERT: "if the object moves at uniform velocity, the height of its velocity-time graph will not change with time."
Direction: Study the following graph and choose the correct options to answer any four questions given below:The velocity-time graph of an object is shown in the following figure.
Q. State the kind of motion that objects has, from A to B and from B to C.- a)Circular motion from A to B
- b)Uniform motion from A to B and non-uniform motion from B to C
- c)Cyclic motion
- d)Non uniform motion from A to B
Correct answer is option 'B'. Can you explain this answer?
Direction: Study the following graph and choose the correct options to answer any four questions given below:
The velocity-time graph of an object is shown in the following figure.
Q. State the kind of motion that objects has, from A to B and from B to C.
a)
Circular motion from A to B
b)
Uniform motion from A to B and non-uniform motion from B to C
c)
Cyclic motion
d)
Non uniform motion from A to B
|
Aditi Bhosale answered |
In the graph, there is a straight line from point A to B and straight line in a velocity-time graph indicates uniform motion and point B to C has negative acceleration(Retardation) which is a non-uniform motion.
Chapter doubts & questions for Motion - Science Class 9 2025 is part of Class 9 exam preparation. The chapters have been prepared according to the Class 9 exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for Class 9 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
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