In 1990, Walter Arfeuille of Belgium lifted a 281.5-kg object through a distance of 17.1 cm using only his teeth. (a) How much work was done on the object by Arfeuille in this lift, assuming the object was lifted at constant speed? (b) What total force was exerted on Arfeuille’s teeth during the lift?

A car with mass 1520 kg is traveling down the highway at a speed of 18 m/s when the driver slams on the brakes due to an accident up ahead. The car eventually comes to rest.According to the work-energy theorem the work is related to the change in kinetic energy, Wnet = Δ KE = KEfinal - KEinitial.(a) Using the work-energy relationship, determine how much net work is done on the car from the brakes? Report the magnitude of the the work (positive value) even though the work from brakes will be negative since the car is slowing down._____ J(b) The brakes apply a force of 24000 N to the car in order to make it stop. Using the fact that W = F d and the fact that the you found the work done (magnitude) by the brakes in part (b), determine the stopping distance, d, of the car.____ m

A bicyclist starting from rest applies a force of F = 239 N to ride his bicycle across flat ground for a distance of d = 210 m before encountering a hill making an angle of θ = 17 degrees with respect to the horizontal. The bicycle and rider have a mass of m = 120 kg combined. In this problem, you can ignore air resistance and other losses due to friction.How much work, W in joules, did the rider do before reaching the hill? What is the bicycle's speed, v in m/s, just before the hill? If the cyclist starts coasting at the bottom of the hill, what distance, di in meters, does the bike travel up the incline?

A rope is tied to a box and used to pull the box 1.5 m along a horizontal floor. The rope makes an angle of 30° with the horizontal and has a tension of 5 N. The opposing friction force between the box and the floor is 1 N. How much work does each of the following forces do on the box: (a) gravity, (b) the tension in the rope, (c) friction, and (d) the normal force? What is the total work done on the box?