Question

Pilings are driven into the ground at a building site by dropping a 1850 kg object onto them. What change in gravitational potential energy does the object undergo if it is released from rest 19.0 m above the ground and ends up 1.90 m above the ground?

Answer 1

Gravitational acceleration = g = 9.81 m/s²

Mass of the object = m = 1850 kg

Height from which the object is dropped = h₁ = 19 m

Height the object ends up at = h₂ = 1.9 m

Change in potential energy of the object = E

The change in potential energy of the object is equal to the final potential energy minus the initial potential energy of the object.

E = -3.1 x 10^5 J

Negative as the object loses potential energy.

Change in potential energy of the object = -3.1 x 10^5 J