[8 points] There are several ways that an inelastic collision may be used to determine the speed of a projectile. Example 8.8 describes a "ballistic pendulum", you might like to take a look at that. Here are two variations: a bullet of mass m is fired into a wooden block of mass M... (a) ... and the block of mass m compresses a spring of spring constant k by distance x. Find an expression for the speed of the bullet. (b) ... and the block of mass m slides distance d across a surface with friction coefficient u. Find an expression for the speed of the bullet.