A 5.00 gram bullet moving horizontally with a speed of 400 m/s collides with a wooden block. After moving 2.00 cm into the block the bullet stops moving. Was work done on the bullet? If so describe the type of work and the force that did the work.     a. yes, negative work, force is in the opposite direction as the initial velocity of the bullet   b. yes, positive work, force is in the same direction as the initial velocity of the bullet   c. yes, positive work, force is in the opposite direction as the initial velocity of the bullet   d. No work was done on the bullet   e. yes, negative work, force is in the same direction as the initial velocity of the bullet

A cat’s crinkle ball toy of mass 15 g is thrown straight up with an initial speed of 3 m/s. Assume in this problem that air drag is negligible. (a) What is the kinetic energy of the ball as it leaves the hand? (b) How much work is done by the gravitational force during the ball’s rise to its peak? (c) What is the change in the gravitational potential energy of the ball during the rise to its peak? (d) If the gravitational potential energy is taken to be zero at the point where it leaves your hand, what is the gravitational potential energy when it reaches the maximum height? (e) What if the gravitational potential energy is taken to be zero at the maximum height the ball reaches, what would the gravitational potential energy be when it leaves the hand? (f) What is the maximum height the ball reaches?

. In the annual Empire State Building race, contestants run up 1,575 steps to a height of 1,050 ft. In 2003, Australian Paul Crake completed the race in a record time of 9 min and 33 S, Mr., Crake weighed 143 lb (65 kg) , (a) How much work did Mr., Crake do in reaching the top of the building? (b) What was his average power output (in ft-lb/s and in hp)?

(a) What is the efficiency of an out-of-condition professor who does 2.10105J of useful work while metabolizing 500 kcal of food energy? (b) How many food calories would a well-conditioned athlete metabolize in doing the same work with an efficiency of 20%?