Heat engine absorbs 2 500 j of heat from a hot reservoir and expels 1 000 j to a cold reservoir. when it is run in reverse, with the same reservoirs, the engine pumps 2 500 j of heat to the hot reservoir, requiring 1 500 j of work to do so. find the ratio of the work done by the heat engine to the work done by the pump. is the heat engine reversible

D. a  bar magnet with its south pole on the left

Yup your right can give me more detail  

For the bullet,  the net force on the bullet: an fbd would look like a dot with a horizontal "friction" force protruding from one end.by newton's 2nd law: we can solve for acceleration since we know  and .we know that  (final velocity is bullet not moving), . we can use the following kinematic equation to get  , or the displacement.so it penetrates  m.