Home › ICSE Class 9 › physics › Motion in One Dimension › A stone is dropped from rest. After 2 seconds it…
A stone is dropped from rest. After 2 seconds its velocity is approximately:
A4.9 m per second
B9.8 m per second
C19.6 m per second
D39.2 m per second
Answer & Solution
Correct answer: C. 19.6 m per second
1. Use v = u + gt with u = 0 (dropped from rest).
2. Take g = 9.8 m per second squared (downward) and t = 2 s.
3. v = 0 + 9.8 × 2.
4. v = 19.6 m per second.
5. Option B gives velocity after 1 s only; option D doubles unnecessarily.
_Source: Selina Concise Physics ICSE Class 9, Ch 2 'Motion in One Dimension' (aplustopper.com extract)_
Related questions
A stone is thrown straight up with initial velocity 20 m per second. Taking g = 10 m per sA car at 36 km/h is brought to rest by uniform retardation in 50 metres. The retardation mA body has zero average velocity over an interval. Which conclusion is FORCED?A body accelerates from 5 m per second to 25 m per second over 4 seconds. The distance covOn a velocity-time graph, the area under the curve represents:A car decelerates uniformly from 20 m per second to rest in 4 seconds. The retardation is:On a displacement-time graph, what does the slope of the line represent?Which equation gives displacement in terms of initial velocity, acceleration and time?