Question

A ball is thrown horizontally from a height of 19 m and hits the ground with a speed that is five times its initial speed. What is the initial speed?

Answer 1

The initial speed of the ball is 3.93 m/s.

Step-by-step explanation:

It is given that,

A ball is thrown horizontally from a height of 19 m, h = 19 m

Let u is the initial speed of the ball so, its final velocity, v = 5u

Using third equation of motion as :

`v^2-u^2=2gh`

`(5u)^2-u^2=2* 9.8* 19`

`24u^2=372.4`

u = 3.93 m/s

So, the initial speed of the ball is 3.93 m/s. Hence, this is the required solution.