While leaning out a window that is 5.70 m above the ground, you drop a 0.600-kg basketball to a friend at ground level. your friend catches the ball at a height of 2.00 m above the ground. determine the following.
(a) the amount of work done by the force of gravity on the ball
(b) the gravitational potential energy of the ball-earth system, relative to the ground when it is released
(c) the gravitational potential energy of the ball-earth system, relative to the ground when it is caught
(d) the ratio of the change (pef − pe0) in the gravitational potential energy of the ball-earth system to the work done on the ball by the force of gravity

Awind turbine is rotating counterclockwise at 0.5 rev/s and slows to a stop in 10 s. its blades are 20 m in length. (a) what is the angular acceleration of the turbine? (b) what is the centripetal acceleration of the tip of the blades at t=0s? (c) what is the magnitude and direction of the total linear acceleration of the tip of the blades at t=0s?

Calculate the numbers of photons having a wavelength of 10.0 mm required to produce 1.0 kj of energycalculate the numbers of photons having a wavelength of 10.0 mm required to produce 1.0 kj of energy

No matter what energy transformation we discuss, we know that no energy transfer is 100% efficient. you are about to enter a bicycle rave. you have trained extensively and eaten well to maximize your energy input throughout the bicycle race. you know that some of your kinetic energy will become wasted energy in the form of heat. what is the source of the heat energy and how can you minimize it to maximize the efficiency of your performance in the race? a) you are the source of the heat energy. you can minimize the heat energy but selecting the appropriate clothes to wear. b) air resistance is the source of he heat energy. you can minimize the air resistance by your position while riding the bicycle. c) friction is the source of the heat energy. you can minimize the friction by lubricating all appropriate parts and keeping the tires well inflated. d) kinetic energy is the source of the heat energy. you can reduce the production of heat energy but minimizing the energy you expend to race on the bicycle.