As a snowboarder descends a mountain slope, gravity, the normal force, and friction combine to exert a net force of 320 N inthe downhill direction. The net force does 4700 J of work on herduring one segment of her descent. If her path cuts across the faceof the mountain at a 65° angle from the direction of the net force,over what distance does she travel?

You drop a 1.50 kg book to a friend who stands on the ground at distance D= 12.0 m below. If your friend's outstretched hands are at distance d = 1.30 mabove the ground (see the figure), (a) how much work W, does the gravitational force do on the book as it drops to her hands? (b) What is the change AU in the gravitational potential energy of the book-Earth system during the drop? If the gravitational potential energy Uof that system is taken to be zero at ground level, what is U (c) when the book is released and (d) when it reaches her hands? Now take U to be 100 J at ground level and again find (e) W, (f)AU. (g) U at the release point, and (h) U at her hands. (a) Number Units (b) Number Units (c) Number Units (d) Number Units (e) Number Units (f) Number Units (g) Number Units (h) Number Units >

A 0.42 kg particle has a speed of 5.0 m/s at point A and kinetic energy of 7.5 J at point B. (a) What is its kinetic energy at A? (b) What is its speed at point B? lea ng m/s (c) What is the total work done on the particle as it moves from A to B? Need Help? Read It ds.

An applied force of 20 N i pushes an object that is initially at rest over a horizontal surface. The coefficient of kinetic friction is 0.450 and the mass is 1.4 kg. If the net work done at some point is 60.6 J, what is the object's speed at that point?