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.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.

false

explanation: