Respuesta :

Answer:

The rock has an impact speed  of 9.9 m/s.

Explanation:

given information:

object's mass, m = 3 kg

height, h = 5 m

in this case, the potential energy is equal to the kinetic energy

PE = KE

mgh = [tex]\frac{1}{2}[/tex] mv²

where

m = mass (kg)

g = gravitational constant (9.8 m/s²)

v = velocity (m/s)

so,

mgh = [tex]\frac{1}{2}[/tex] mv²

gh = [tex]\frac{1}{2}[/tex] v²

v² = 2gh

v = √2gh

  = √(2)(9.8)(5)

  = 9.9 m/s