A body starts from rest with uniform acceleration and travels a distan...
Problem: A body starts from rest with uniform acceleration and travels a distance of 9 is 525 of Total distance in last second of its journey. Find how much time body is in motion and how much distance travel is if it covers 6 metre in 1 second?
Solution:
Given:
- The body starts from rest.
- The body has a uniform acceleration.
- The distance travelled in the last second of the journey is 9/525 of the total distance.
- The body covers 6 metres in 1 second.
To find:
- The time for which the body is in motion.
- The total distance travelled by the body.
Assumptions:
- The acceleration is constant throughout the journey.
- The journey is in a straight line.
Approach:
- Use the equations of motion to find the time and distance travelled by the body.
- Use the given information to solve for the unknowns.
Equations of Motion:
- v = u + at
- s = ut + 1/2 at^2
- v^2 = u^2 + 2as
Calculation:
- Let the initial velocity of the body be u and the acceleration be a.
- Let the total distance travelled by the body be S and the time for which it is in motion be t.
- From the given information, we know that the distance travelled in the last second of the journey is 9/525 of the total distance. Therefore, the distance travelled in the last second is (9/525)S.
- We also know that the body covers 6 metres in 1 second. Therefore, the final velocity of the body is 6 m/s.
- Using the first equation of motion, we can find the time taken by the body to reach a velocity of 6 m/s:
v = u + at
6 = 0 + at
t = 6/a
- Using the third equation of motion, we can find the total distance travelled by the body:
v^2 = u^2 + 2as
(6)^2 = 0^2 + 2aS
S = 18/a
- Using the second equation of motion, we can find the distance travelled by the body in the last second of the journey:
s = ut + 1/2 at^2
s = 0(1) + 1/2 a(1)^2
s = 1/2 a
- From the given information, we know that (9/525)S = s. Substituting the values of S and s, we get:
(9/525)(18/a) = 1/2 a
- Solving for a, we get:
a = 7.5 m/s^2
- Substituting the value of a in the equations for t and S, we get:
t = 0.8 s
S = 24 m
Answer:
- The body is in motion for 0.8 seconds.
- The total distance travelled by the body is 24 metres.
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