11. (10 pts) A chunk of space rock fall to the earth from the distance of the moon. As it is falling, A. The object’s kinetic energy decreases*B. The object’s gravitational potential energy decreases C. The object’s angular momentum increasesD. The object's momentum stays the sameE. The object’s total mechanical energy decreases
12. (10 pts) The diagram below shows a snapshot at one time of a string with a purely transverse wave traveling along it to the right. Eight points on the string are indicated. (The points are points on the string, not phases of the wave. They move up and down with the string, not to the right.)A.Which points have a speed of zero? B.Which points have an acceleration of zero? (a, e)C.Which points are moving upward (↑)? (d, e, f)D.Which points are moving downward (↓)? (a, b, h)E.Which points are accelerating upward? (f, g, h)F. Which points are accelerating downward? 13. (10 pts) An airport worker near a jet experiences a sound intensity 16 times the safe level. In order to decrease the his sound exposure to the maximum safe level he needs to increase his distance from the jet by a factor of E. 32 14. (10 pts) The Bernoulli equation is really a statement of *A. energy conservation for a moving fluidB. Newton's third law, i.e., action and equal reactionC. Conservation of linear momentumD. F=ma as applied to a fluidE. the continuity principle for mass conservation 15. (10 pts) Shown is a wave traveling along a clothesline. The line is tied at one end and the other end is tied to a ring free to move on a pole. The tension force remains the same. Which of the following figures show the form of the wave when it travels back toward the tied end?
16. (30 pts) Survivors of mass m=70 kg from a shipwreck spot a cylindrical wooden log with length L=5m and diameter D=1.5m and mass M=600 kg. Give an expression for N, the number of people that the log can support before it is completely submerged in terms of the other given constants and any needed constant values. Then compute a value for N. (Assume that the people are entirely out of the water on top of the log).
You've reached the end of your free preview.
Want to read all 8 pages?