Homework Statement
When a person parachutes, the impact velocity is equal to that attained in free fall from a height of 4.5 m. After contacting the ground, the jumper’s momentum is quickly brought to zero by the earth. Assuming that the person has a mass of 80 kg, what is the average force on...
Homework Statement
A 200 kg boulder falls from rest off a 120.0 m high cliff. If the boulder experiences a frictional force of 280 N[U] as it falls, what would be the velocity just before it hits the ground?
Homework Equations
kinetic energy = (1/2)mv2
gravitational potential energy =...