A boy standing at the top of a tower of 20 m height drops a stone. Assuming g = 10 m s-2, the velocity with which it hits the ground is
- 10.0 m/s
- 20.0 m/s
- 40.0 m/s
- 5.0 m/s
Answer
(2) 20.0 m/s
Solution
The stone is dropped, so u = 0.
v2 = u2 + 2gh
v = 2gh = 2 10 20
= 400 = 20 m/s
Answer: (2)