22. what is the force exerted by a pressure of 720 lb/in? on a hydraulic piston with a
radius of 1.5 inches? (first: use the area formula for a circle (a = ar to get the surface
area of this circular piston.)

The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.