4. A 22.0 kg child is riding a playground merry-go-round that is rotating at 40.0 rev/min. What centripetal acceleration does she experience to stay on if she is 1.25 m from its center? 5. The driver of a 1000-kg car tries to turn through a circle of radius 100 m on an unbanked curve at a speed of 16.0 m/s. The kinetic friction coefficient between the tires and slippery road is u = 0.25. First calculate (a) the magnitude of friction and (b) centripetal force required to make the circular turn. (c) Can the driver make the circular turn without slipping? (a) f = (b) F = (c) 6. A pendulum that consists of a ball (m = 1.50 kg) attached to a light cord rotates in a circular path of radius r = 0.800 m at constant speed v, as shown in Figure. Here the angle 0 = 65°, and we ignore air friction and assume the mass of the light cord is negligible. %3D %3D (a) Calculate the tension T in the cord. T.

4. A 5 Kg cat sits 2 m from the center of a merry go round. The merry go round is set in motion, and the cat's tangential speed is 3 m/s.     (a) What is the cat centripetal acceleration?     (b) What is the centripetal force acting on the cat?

3. A roller coaster is built so that there is a circular curve of radius 80.0 m at the top of one hill. The speed with which the car goes over the hill varies. Assume the passenger has a mass of 50.0 kg. The cars have wheels over and under the track so that it stays on and the passenger is wearing a seatbelt. a. If the speed is 20.0 m/s going over the top what is the force on the passenger? Force factor? Is the force from the seat or the belt?

It has been suggested that rotating cylinders about 18.5 mi long and 4.60 mi in diameter be placed in space and used as colonies. What angular speed must such a cylinder have so that the centripetal acceleration at its surface equals the free-fall acceleration on Earth? rad/s