Question

A person jumps from the roof of a house 3.1-m high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.70 m. If the mass of his torso (excluding legs) is 42kg .
Part A
Find his velocity just before his feet strike the ground.
Express your answer using two significant figures. Enter positive value if the velocity is upward and negative value if the velocity is downward.

Answer 1

Part A

Free fall motion
h = 3.1 m

Equation: Vf = √(2gh) = √(2*9.8 m/s^2 * 3.1 m) = 7.8 m/s

That is the only part in the question.