If a resident accidentally causes a chunk of ice to fall from the roof, how fast would the ice be moving when it hits the ground? Neglect air resistance.

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

the correct choice is a .

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