Question

A rocket is moving in a gravity free space with a constant acceleration of 2 metre per second square along positive x direction

Answer 1

Answer:

8 sec

Explanation:

Remaining part of question:

A ball is thrown from the left end of the chamber in + x direction with a speed of 0.3 m/s relative to the rocket. At the same time, another ball is thrown in -x direction with a speed of 0.2 m/s from its right end relative to the rocket. The time in seconds when the two balls hit each other is ?

Ans:

If rocket accelerates by 2 m/s2 in +x direction, then balls inside it also accelerates with it with same value and in same direction in ground frame. Thus when we switch to frame of the rocket there is no acceleration on balls. Inside that frame we should impose the concept of relative velocity and convert this two body problem to one body. Velocity of left ball relative to right ball = 0.3 m/s + 0.2 m/s = 0.5 m/s in +x direction. Thus time taken to collide = distance/Velocity of left ball relative to right ball = 4/0.5=8 seconds.

Answer 2

From reference frame of rocket the magnitude of relative velocity of one ball

(0.2)+(0.3)=(0.5)m/s

Time taken= relative separation /relative velocity

=4/0.5=8