In rewinding an audio or video tape, why does the tape wind up fastest at the end?
An early method of measuring the speed of light makes use of a rotating slotted wheel. A beam of light passes through a slot on the outside edge of the wheel, travels to a distant mirror, and returns to the wheel just in time to pass through the next slot in the wheel. One such slotted wheel has a radius of 5.0 cm and 500 slots at its edge. Measurements taken when the mirror was 500 m from the wheel indicated a speed of light of 3.0x108 m/s. a) What was the (constant) angular speed of the wheel? b) What was the linear speed of a point of the edge of the wheel?
A marksman on a merry-go-round fires at a target on the ground near the merry-go-round. How should he adjust his aim to account for the fact he is on the merry-go-round? What if the target were on the merry-go-round and the marksman were standing on the ground?
A wheel (call it wheel A) of radius r=10 cm is coupled by a rubber fanbelt to a different wheel (call it B) of radius r=25 cm. Wheel A increases its angular speed from rest at a uniform rate of 1.6 rad/s2. Find the time for wheel B to reach a rotational speed of 100 rev/min, assuming the belt does not slip.
Consider a right cylindrical can with mass M, height H, and uniform density that is initially filled with soda pop of mass m. Small holes are punched in the bottom and top of the can and the liquid slowly drains out. What is the height h of the center of mass of the can and pop system initially? What is the center of mass of the system after all the liquid has drained out (ignore the soda on the floor). If x is the height of the remaining soda pop at any given instant, find x (in terms of M, H, and m) when the center of mass reaches its lowest point.