Question

1. (5 pts.) When a marble at rest hangs by a single vertical string, tension in the string is mg. If the marble is made to move in a horizontal circle so that the string traces a cone, string tension is

              A. mg                  B. > mg               C. < mg                                                                                                        D. may be > or < mg depending on the speed of the marble.

2. (10 pts.) Basketball player Darrell Griffith (weight 220 lbs) is on record for a standing vertical jump of 4 ft. This means he moved upward by 4 ft after his feet left the floor. What was his speed as he left the floor?

3. (10 pts) A typical baseball has a mass of 145 g. The fasted pitched baseball was measured at 105 mph. If is the pitcher exerted his force (assumed to be horizontal and constant) over a distance of 1.0 m, (a) what force did the pitcher produce on the ball during his record setting pitch? (b) What was the kinetic energy of the ball just after it left his hand?

Answer 1