Answer:
v = √2gh
v = 7 m / s
Explanation:
For this exercise we can use the law of conservation of energy
starting point. In the roof
Em₀ = U = m g h
final point. On the floor
Em_f = K = ½ m v²
as there is no friction, the energy is conserved
Em₀ = Em_f
m g h = ½ m v²
v = √2gh
In the exercise the height of the ceiling is not indicated, but in general the height of the ceiling of a house is h = 2.5 m
v = √ (2 9.8 2.5)
v = 7 m / s
