A block of plastic (0.7 kilogram) is sitting on a rough horizontal plane (μk = 0.4). A bullet (mass 1.2 gram) is shot at the block and passes through it. It strikes a wall a short time later and you compute that the bullet exits the block with speed 250 m/s. After the bullet passes through, the block travels 0.75 meter before coming to rest.
a) Find what is the speed of the block after the bullet passes through it?
b) Find what is the speed of the bullet just before it strikes the block?