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π radian is equal to 180 ° . Radian is a unit of measurement for angles, just like degrees are, and π is just the no. of radians that makes up that angle.
Statement A: Uniform circular motion is a case of accelerated motion
Statement B: In third equation of motion we do not have the time.
Uniform circular motion is always accelerated because the direction of velocity is continuously changing hence velocity is changing which causes change in acceleration. Hence the given statement is true.
There are 3 equations of motion,
As, we can see there , we don't have the time in the third equation of motion.
Which of the following is correct about uniform circular motion?
A. Direction of motion is continuously changed
B. Direction of motion is not changed
C. Speed and direction both remain constant
D. Speed is constant, but direction is changing
Uniform circular motion is accelerated because the velocity changes due to continuous change in the direction of motion. So, even when the body moves ta a constant speed, its velocity is not constant. Thus, for a body moving in a circular path at a constant speed, its velocity changes continuously. The change in velocity gives rise to an acceleration in the moving body. Therefore circular motion is an acceleration motion even when the speed remains constant.
Which of the quantities – speed, time, velocity and acceleration have the same SI unit?
When the velocity decreases with respect to time it is termed as retardation or deceleration. In reality negative acceleration is commonly called retardation. Its SI unit. is m/s^{2}.
A bus moves from stop ‘A to stop ‘B’ with a speed of 40 km/hr and then from stop ‘B’ to stop ‘A with a speed of 50 km/hr. Its average speed is
Let the distance between A and B be D and time taken to cover the distance be T1 and T2.
Speed = Distance/Time
40 = (D/T1) and 50 = (D/T2)
T1 = (D/40)
also, T2 = (D/50)
Total time (T) = T1 + T2
⇒ (D/40) + (D/50) = (9D/200)
Total Distance = (D + D) = 2D
Average speed = Total Distance/Total Time Taken
= (2D/(9D/200)) = 400/9 = 44.4 km/hr
When a body moves with constant speed its acceleration is zero . The body is said to be accelerating if it moves in a uniform circular motion. The slope of the velocity time graph gives Instantaneous acceleration . All the given statements are correct. Therefore , option ( d) is correct answer.
Vector A physical quantity having a magnitude as well as direction is known as vector quantity.
Odometer  an instrument for measuring the distance travelled by a wheeled vehicle.
Acceleration of a body is defined as the rate of change of its velocity with time.
Scalar  A physical quantity having only magnitude is known as a scalar quantity.
The correct answer is B as velocitytime graph we will get displacement travelled.as ,displacement=velocity/time
The graph shown above is not possible in case of Velocity  time graph. Graph may be straight curved but not completely circular.
Yes, a body can have a constant speed and still be accelerating.
Acceleration can be either due to change in speed or due to direction of motion or both.
Consider an example of a uniform circular motion. In a uniform circular motion, the body moves with a constant speed but we still say that it is accelerating due to the change in direction
This acceleration is called centripetal acceleration and is given as
a_{c }= −v^{2}/r
where v= constant speed
and r= radius of circle
If we get a curve line in displacement – time graph then the velocity is
Which of the following statement is correct?
A. When a body starts from rest, u = 0
B. When a body comes to rest, V = 0
C. For a body under free fall, a = −9.8m/s^{2}
D. For uniform velocity, a = 0
Acceleration is positive in the “down” direction, where “down” is where the nearest big source of gravity is.
In physics, acceleration is usually expressed as a vector, i.e. a direction and a magnitude. A magnitude is an absolute value, hence always positive.
Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion.
A body is moving with a velocity of 10m/s. If the motion is uniform, what will be the velocity after 10 second?
As the body is moving in uniform motion, so the acceleration will be zero.
as acceleration is zero, the change in velocity is also zero.it means velocity will be the same in whole motion.
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