1. A machine gun is fired at a steel plate. Is the average force on the plate from the bullet impact greater if the bullets bounce off or if they are squashed and stick to the plate? Why?
2. A 5.00 g bullet is shot through a 1.00 kg wood block suspended on a string 2.000 m long. The center of mass of the block rises a distance of 0.45 cm. Find the speed of the bullet as it emerges from the block if its initial speed is 400 m/s.
3. Ken and Kim are skating together on a rink at 3.00 m/s. Ken keeps asking Kim how much she weighs. Annoyed, Kim pushes away from Ken so that she speeds up to 4.00 m/s and he slows down to 2.25 m/s in the same direction. Friction, in the physics sense, is negligible in this drama. If Ken weighs 800 N, what does Kim weigh?
4. In a zero-gravity environment, can a rocket-propelled spaceship ever attain a speed greater than the relative speed with which the burnt fuel is exhausted?
5. A 20.0 kg projectile is fired at an angle of 60.0 degrees above the horizontal and with a speed of 240 m/s. At the highest point of its trajectory the projectile explodes into two fragments with equal mass, one of which falls vertically with zero initial speed. a) How far from the point of firing does the other fragment strike if the terrain is level? b) How much energy is released during the explosion?

If you still have time, feel free to discuss material/problems relevant for Thursday's exam. You also might begin discussing what your group(s) might do for the P113 project. My advice is to go ahead and get much of it out of the way relatively soon. The latter part of the semester tends to be very hectic for most of you.