Question

A stone is released from rest from the edge of a building roof 190 m above the ground. Neglecting air resistance, the speed of the stone, just before striking the ground, is:___________.

Answer 1

61 m/s

Step-by-step explanation:

• If the stone is realeased from rest, this means that its initial velocity is 0.
• As tha stone is only influenced by gravity, and the acceleration due to it is constant (near the surface of the Earth), we can apply the following kinematic equation:

`v_(f)^(2) - v_(o)^ {2} = 2* g* h (1)`

• Replacing by the values of g=9.8 m/s², and h=190 m, rearranging and solving for vf, we get:

• vf = √2*g*h =√2*9.8 m/s²*190 m = 61 m/s (assuming that the downward direction is the positive one).