An athlete at the gym holds a 2.5 kg steel ball in his hand. His arm is 70 cm long and has a mass of 4.0 kg. a) What is the magnitude of the torque about his shoulder if he holds his arm straight out to his side, parallel to the floor?
b) What is the magnitude of the torque about his shoulder if he holds his arm straight, but 55? below horizontal?

Which statement is true for light passing into a medium that is more optically dense than the first medium through which it past

Suppose that two tanks, 1 and 2, each with a large opening at the top, contain different liquids. a small hole is made in the side of each tank at the same depth 1.57 m below the liquid surface, but the hole in tank 2 has 2.49 times the cross-sectional area of the hole in tank 1. (a) what is the ratio ρ1/ρ2 of the densities of the liquids if the mass flow rate is the same for the two holes? (b) what is the ratio rv1/rv2 of the volume flow rates from the two tanks? (c) at one instant, the liquid in tank 1 is 14.9 cm above the hole. if the tanks are to have equal volume flow rates, what height above the hole must the liquid in tank 2 be just then?

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final