Q 11-05-055JEE MainJEE Main 2026 (2 Apr, Shift 2)Easy
A spherical ball of mass $2$ kg falls from a height of $10$ m and is brought to rest after penetrating $10$ cm into sand.
The average force exerted by sand on the ball is ______ N.
(Take $g=10\ \text{m/s}^2$)
Answer: (B) $2020$
Apply the work-energy theorem from release to rest. The ball starts and ends at rest, so total work is zero.
Gravity acts through $10+0.1=10.1$ m; the sand's average force $F$ acts through $0.1$ m:
$$mg(10.1)-F(0.1)=0\ \Rightarrow\ F=\frac{2\times10\times10.1}{0.1}=2020\ \text{N}$$
Solution by Sreeraj P, M.Sc Physics