( ignore air resistance and gravity ) During a flood a tree truck of mass 100 kg falls down a waterfall. The waterfall is 5 m
high. Calculate..
a) the potential energy of the tree trunk at the top of the waterfall.
b) the kinetic energy of the tree trunk at the bottom of the waterfall.
c) the velocity of the tree trunk at the bottom of the waterfall.

To do work, this truck uses energy stored in chemical fuel and an electrical battery. how much total energy does this truck put out?

Aplayground merry-go-round has a radius of 4.6 m and a moment of inertia of 200 kg-m2 and turns with negligible friction about a vertical axle through its center. a child applies a 26.0 n force tangentially to the edge of the merry-go-round for 15.0 seconds. if the merry-go-round is initially at rest, how much work did the child do on the merry-go-round?

Aballoon is rising vertically upwards at a velocity of 10m/s. when it is at a height of 45m from the ground, a parachute bails out from it. after 3s he opens his parachute and decelerates ata a constant rate 5m/s. when. (a) what was the height of the parachutist above the ground when he opened his parachute? (b)how far is the parachutist from the balloon at t=3s? (c)with what velocity does the parachutist hit the ground? (d)after how long does the parachutist hit the ground after his exist from the balloon?