Calculate the change in potential energy of a 91.2 kg man when he takes an elevator from the first floor to 37th floor, if the distance between floors is 3.99 m.

128379.69 J

Explanation:

Potential energy: This can be defined as the energy of a body to to position in the gravitational field. The S.I unit of potential energy is Joules (J).

The expression for potential energy is given as,

ΔEp  = mgΔH

ΔEp = mg(H₂-H₁) Equation 1

Where ΔEp =change in  Potential Energy, m = mass of the man, g = acceleration due to gravity, H₂ = Height of the 37th floor, H₁ = height of the first floor

Given:m = 91.2 kg, g = 9.8 m/s², H₁ = 3.99 m, H₂ = 3.99×37 = 147.63 m.

Substitute into equation 1

ΔEp = 91.2(9.8)(147.63-3.99)

ΔEp = 893.76(143.64)

ΔEp = 128379.69 J.

c. newton's third law of motion