UPSC Prelims 1999 · General Studies
Question 145: Science and Technology
A hunter aims his gun at a point between the eyebrows of a monkey sitting on a branch of a tree. Just as he fires, the monkey jumps down. The bullet will
AnswerThe answer is (a).
In time t the bullet falls (1/2) g t squared below the line of sight, and the monkey falls the same distance from the point aimed at. So at every moment the bullet is level with the monkey's aimed point, and it hits the monkey there, provided the monkey is still in the air when the bullet arrives. Remember: gravity acts equally on both, so aiming straight at the monkey works.
Why each option is right or wrong
- (a) Right. Both fall by the same amount, so the bullet hits at the point aimed.
- (b) Wrong. The monkey falls the same distance, so the bullet does not hit lower.
- (c) Wrong. The bullet is not lifted above the line of aim.
- (d) Wrong. It would miss only if the monkey reached the ground first, which is not assumed.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1999, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.