Q 11-04-005NEETNEET 2025Top questionEasy
A ball of mass $0.5$ kg is dropped from a height of $40$ m. The ball hits the ground and rises to a height of $10$ m. The impulse imparted to the ball during its collision with the ground is (Take $g = 9.8\ \text{m/s}^2$)
Answer: (A) $21$ N s
Concept. Impulse $=$ change in momentum; the velocity reverses.
Step 1. Speeds. Before: $\sqrt{2 \times 9.8 \times 40} = 28$ m/s down; after: $\sqrt{2 \times 9.8 \times 10} = 14$ m/s up.
Step 2. Impulse. $0.5 \times (28 + 14) = 21$ N s.
Answer. $21$ N s (Option A).
Solution by Sreeraj P, M.Sc Physics