contestada

A ball thrown horizontally from a point 24 m above the ground, strikes the ground after traveling horizontally a distance of 18 m. With what speed was it thrown, assuming negligible air resistance

Respuesta :

First of all we get the time of flight from the vertical component:
s
=
1
2
g
t
2

t
=
√
2
s
g

t
=
√
2
×
24
9.8

t
=
2.21
s

The horizontal component of velocity is constant so:
v
=
s
t
=
18
2.21
=
8.14
m/s