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

Answer:

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

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 :

$v^2-u^2=2gh$

$(5u)^2-u^2=2\times 9.8\times 19$

$24u^2=372.4$

u = 3.93 m/s

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