Question

please answer the question
i will mark brainlist

Answer 1

Here is your answer. If you are satisfied with the answer please do mark me as brainliest.

When the child is standing on the trolley, both child and trolley are moving with the same velocity = v

So, their centre of mass is also moving with the velocity of the vehicle,

vcom = mv + Mv / (m + M) = v

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the velocity of centre of mass changes only if the system is subjected to net external force. But since the only forces involved in the child + trolley system are internal(action-reaction pair) when the child runs on the trolley. Therefore, the velocity of their centre of mass will remain unchanged. It will be v

Thus the answer is option 3.