A student lifts 100 N of books 1 m to his shoulder. He walks forward
10 m to the stairs and goes up 3 m. He walks 20 m forwards to class,
How much work has been done to the books?

In what direction does the medium move relative to the direction of the wave? explain.

The crank oa rotates in the vertical plane with a constant clockwise angular velocity ω0 of 5.6 rad/s. for the position where oa is horizontal, calculate the force under the light roller b of the 10.6-kg slender bar ab.

Assume that a person skiing high in the mountains at an altitude of h = 15100 ft takes in the same volume of air with each breath as she does while walking at sea level. determine the ratio of the mass of oxygen inhaled for each breath at this high altitude compared to that at sea level. assume that the air composition (i. e. % of air that is oxygen) is the same at sea level as it is at 15100 ft.