Question

A ball is dropped on top of a building.

a) What is the initial velocity of the ball?

b) What is the height of the building if the ball reaches the floor in 5 s ?

c) What is the velocity of the ball just before it hits the ground?​

Answer 1

Explanation:

a) Initial velocity u will be zero as the ball is just dropped that means it starts from zero.

i.e u=0

b) we know that s=ut+1/2at²

since a=g=10m/s²

so s=0(5)+1/2(10)(5)²

s=1/2(10)(25)

s=5(25)=125m

so height of the building is 125 meters

c)since v=u+at

v=0+10(5)

v=50m/s downwards

so magnitude of velocity of the ball just before hitting the ground will be 50m/s