15. Two men are pushing on opposite sides of a box with a MASS of 30 kg. The man on the left is pushing with a force of 120 N, while the man on the right is pushing with a force of 80 N. The box is accelerating at a rate of 0.5
m/s/s from left to right. For this problem, we need to consider friction.
a. List all of the interactions and draw a free body diagram of all of the forces acting on the box.
b. Write your Net Force Equations.
c. Find the force due to friction acting on the box.
d. What is the size of the Normal force exerted on the box by the ground?
e. What is the coefficient of friction (u) between the box and the ground?

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.