Determine how much work is needed to lift a 3.06 kg object from the bottom of an 8.5 m deep well?
A sled and rider having a combined weight of 69 kg are at rest on the top of a hill 30 m high.
(i) Determine their net energy at the top of the hill?
(ii) Supposing there is no friction, determine the net energy on sliding halfway down the hill?