Question

A stone is dropped from the top of a tower 40 metre high. Its velocity after it has fallen for 2s is:
(Take g = 10m/s2).
(A) – 10 m/s
(B) 10 m/s
(C) – 20 m/s
(D) 20 m/s

Answer 1

Answer:

ans c) -20m/s

v=u + at

v=-10*2

v=-20m/s

Answer 2

A stone is dropped from the top of a tower 40 metre high. Its velocity after it has fallen for 2s is:

(Take g = 10m/s2).

(A) – 10 m/s

(B) 10 m/s

(C) – 20 m/s

(D) 20 m/s

answer : option (C) -20 m/s

explanation : A stone is dropped from the top of a tower 40m high.

initial velocity, u = 0

acceleration acting on the stone, a = g = -10m/s² [ negative sign shows that it is acting downward direction ]

time , t = 2s

using formula,

v = u + at

= 0 + (-10) × 2 = -20m/s

hence, velocity after 2s = -20m/s