Question

A ball is thrown horizontally from the top of a building 109 m high. The ball strikes the ground at a point 75 m horizontally away from and below the point of release. What is the speed of the ball just before it strikes the ground? (note: speed is magnitude of velocity at that point).

Answer 1

Answer:

The speed of the ball just before it strikes the ground is 15.90 m/s.

Explanation:

Given that,

Height = 109 m

Distance = 75 m

We need to calculate the time

Using formula for horizontal projectile

$t=\sqrt{\dfrac{2h}{g}}$

Where, h = height

Put the value into the formula

$t=\sqrt{\dfrac{2\times109}{9.8}}$

$t=4.716\ sec$

We need to calculate the speed of the ball just before it strikes the ground

Using formula of speed

$v =\dfrac{d}{t}$

Where, v = speed

d = distance

t = time

Put the value into the formula

$v=\dfrac{75}{4.716}$

$v=15.90\ m/s$

Hence, The speed of the ball just before it strikes the ground is 15.90 m/s.