Serway & Jewett — Angular Momentum: Problem 30

A 0.005 00-kg bullet traveling horizontally with a speed of $1.00 \times 10^3\text{ m/s}$ strikes an 18.0-kg door, embedding itself 10.0 cm from the side opposite the hinges as shown in Figure P11.30. The 1.00-m wide door is free to swing on its frictionless hinges. (a) Before it hits the door, does the bullet have angular momentum relative to the door's axis of rotation? (b) If so, evaluate this angular momentum. If not, explain why there is no angular momentum. (c) Is the mechanical energy of the bullet-door system constant during this collision? Answer without doing a calculation. (d) At what angular speed does the door swing open immediately after the collision? (e) Calculate the total energy of the bullet-door system and determine whether it is less than or equal to the kinetic energy of the bullet before the collision. (f) What If? Imagine now that the door is hanging vertically downward, hinged at the top, so that Figure P11.30 is a side view of the door and bullet during the collision. What is the maximum height that the bottom of the door will reach after the collision?