posted by Hayden .
A bullet of mass 10 g has a speed of 500 m/s. a) What is its kinetic energy? b) if it penetrates a block of wood a distance of 10 cm before coming to rest, what is the average frictional force stopping the bullet? A second bullet identical to the first is shot through a sheet of wood 5 cm thick. c) With what speed does the second bullet exit the wood?