Question

A ball rolls off an 8.0 m high building and strikes the ground 5.0 m away from the base of the building. How fast was the ball rolling?

Answer 1

Answer: horizontal speed is 3.9 m/s

Explanation: when ball starts to drop, its vertical speed v0 is zero.

We can calculate dropping time from s = v0t +0.5gt².

Dropping time t= √(2s/g)= √((2·8.0 m)/9.81 m/s²)= 1.277 s

Because ball travels horizontal distance s= 5.0 m

HorizontalSpeed v = s/t = 5.0 m/1.277s= 3,915 m/s