A roller coaster is at the top of a 72m hill and weighs 966N. At the top of the hill the coaster car has
energy. Calculate it.

Henry, whose mass is 95 kg, stands on a bathroom scale in an elevator. the scale reads 830 n for the first 2.4 s after the elevator starts moving, then 930 n for the next 2.4 s. part a what is the elevator's speed 4.8 s after starting? express your answer with the appropriate units.