Question

A particle is found to be at rest when seen from a frame $S_1$ and moving with a constant velocity when seen from another frame $S_2$. Mark out the possible option.

• A. Both the frames are inertial
• B. Both the frames are non-inertial
• C. $S_1$ is inertial and $S_2$ is non-inertial
• D. $S_1$ is non-inertial and $S_2$ is inertial

Answer 1

Answer: (A), (B)

The correct options are
A Both the frames are inertial
B Both the frames are non-inertial

Assume one inertial frame in which particle is at rest. Let it be $S_1$, and second frame $S_2$, which is moving with constant velocity. For $S_2$, particle will now be seen moving with constant velocity. So, Option A is correct.

Now assume $S_{1}and{S}_2$ are non- inertial frames moving in same direction with same acceleration as that of particle.

Now, assume at this moment, velocity of particle and $S_1$ is same, so particle will be seen at rest from $S_1$.

Now, for same moment of time, let $S_2$ have different velocity than particle, so from $S_2$ particle will now be seen as moving with constant velocity. So, option B is also correct.

Options C and D are false as condition is not possible for different types of frames.