1998 General Studies, all questions
UPSC Prelims 1998 · General Studies
Question 114: Science and Technology
A ball is dropped from the top of a high building with a constant acceleration of 9.8 m/s². What will be its velocity after 3 seconds?
a9.8 m/s
b19.6 m/s
c29.4 m/s
d39.2 m/s
AnswerThe answer is (c).
For a body dropped from rest with constant acceleration, v = u + at = 0 + 9.8 x 3 = 29.4 m/s after 3 seconds. After one second it would be 9.8 m/s, after two 19.6 m/s, after three 29.4 m/s, and after four 39.2 m/s.
Why each option is right or wrong
- (a) 9.8 m/s is the velocity after one second.
- (b) 19.6 m/s is the velocity after two seconds.
- (c) Right: 9.8 x 3 = 29.4 m/s.
- (d) 39.2 m/s is the velocity after four seconds.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1998, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.