MPSC State Service 2020 · CSAT · Question 22 of 77

Two balls of unequal mass are dropped from the same height. If the gravitational force is assumed to be constant, then the theory predicts that they will hit the Earth՚s surface at the same time. If the actual force is used instead, then the theory predicts:

Reading Comprehension

Athat the ball with the larger mass will hit first.
Bthat the ball with the smaller mass will hit first.
Cthat they will hit at the same time.Correct
Dnothing, since the equation of motion cannot be solved without the constant force approximation.

Answer: C. that they will hit at the same time.

Explanation

With the actual inverse-square force, the heavier ball's greater gravitational pull on the Earth system makes it hit marginally first: the larger mass hits first.

Source: MPSC Rajyaseva Prelims 2020 – CSAT Paper II (Set C), official paper

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