6. A 2.2 kg rock rests on the edge of a bridge that is 3.3 m above a river. What is the gravitational potential energy of the rock when measured from the surface of the
river? What is the gravitational potential energy when measured from the edge of
the bridge?

An apple is falling from a tree. disregarding air resistance, which diagram shows the free-body diagram of the force or forces acting on the apple?

Amachinist turns the power on to a grinding wheel, at rest, at time t = 0 s. the wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 96 rad/s. the wheel is run at that angular velocity for 40 s and then power is shut off. the wheel slows down uniformly at 1.5 rad/s2 until the wheel stops. in this situation, the time interval of deceleration is closest to:

Efficiency is the ratio of to for a system a)power in to power in b)power in to power out c) power out to power out d) power out to power in