Chapter 9, Problem 21P

A typical road bike wheel has a diameter of 70 cm including the tire. In a time trial, when a cyclist is racing along at 12 m/s:a. How fast is a point at the top of the tire moving?b. How fast, in rpm, are the wheels spinning?

A block is sliding (without friction) down a ramp. A ring, a disc and a solid sphere are rolling (without slipping) down the same ramp. The height of the ramp is 46 meters.What is the speed of the ring at the bottom of the ramp? in m/s   What is the speed of the disc at the bottom of the ramp? in m/s   What is the speed of the solid sphere at the bottom of the ramp? in m/s   What is the speed of the block at the bottom of the ramp? in m/s

Figure P9.75 shows a 100 g puck revolving at 100 rpm on a 20-cm-radius circle on a frictionless table. A string attached to the puck passes through a hole in the middle of the table. The end of the string below the table is then slowly pulled down until the puck is revolving in a 10-cm-radius circle. How many revolutions per minute does the puck make at this new radius?

A light, rigid rod is 68.5 cm long. Its top end is pivoted on a frictionless horizontal axle. The rod hangs straight down at rest with a small, massive ball attached to its bottom end. You strike the ball, suddenly giving it a horizontal velocity so that it swings around in a full circle. What minimum speed at the bottom is required to make the ball go over the top of the circle?

Two bugs, Buzz and Crunchy, are siting on a spinning disk. Buzz is sitting halfway and Crunchy is sitting at the outer edge as shown. The radius of the disk is 1.6 m and the disk is rotating with an angular speed of 33 rpm. What is Crunchy's speed, in m/s?

Chad gets on a roller coaster. Chad and the cart rolls down the frictionless loop with a constant speed of 7.4 m/s. The mass of Chad and the cart is 0.75 kg and the radius of the loop is 0.86 m. Since the cart has a smaller dimension than the loop, the cart can be viewed as a point particle. What is the normal force at the top and bottom points? The magnitude of the gravitational acceleration is 9.8 m/s^2. Draw a free body diagram.

A car initially traveling eastward turns north by traveling in a circular path at uniform speed as shown in Figure P7.15. The length of the arc ABC is 235 m, and the car completes the turn in 36.0 s. (a) Determine the car’s speed. (b) What is the magnitude and direction of the acceleration when the car is at point B?

There is a clever kitchen gadget for drying lettuce leaves after you wash them. It consists of a cylindrical container mounted so that it can be rotated about its axis by turning a hand crank. The outer wall of the cylinder is perforated with small holes. You put the wet leaves in the container and turn the crank to spin off the water. The radius of the container is 15.0 cm. When the cylinder is rotating at 1.64 revolutions per second, what is the magnitude of the centripetal acceleration at the outer wall?

A tennis ball, starting from rest, rolls down the hill in the figure. At the end of the hill the ball becomes airborne, leaving at an angle of 35° with respect to the ground. Treat the ball as a thin-walled spherical shell, and determine the range x. 1.8 m 35 D