Monday 6/8PHYS 2010

Nathalie HoffmannUniversity of Utah

Uniform Circular Motion

• An object on a circular path accelerates even if its speed is constant.

Centripetal acceleration

• Always points radially inward (toward center of curvature)

Practice Problems

• A ball spins on a 0.870-m-long string with a constant speed of 3.36 m/s. Calculate the acceleration of the ball. Be sure to specify the direction of the acceleration.

• The space shuttle is in orbit about 300 km above the surface of Earth. The period of the orbit is about 5.43 × 103 s. What is the acceleration of the shuttle? (The radius of Earth is 6.38 × 106 m.)

• Modern pilots can survive radial accelerations up to 9g (88 m/s2). Can a fighter pilot flying at a constant speed of 500 m/s and in a circle that has a diameter of 8800 m survive to tell about his experience?

Answers

• P1.1: 13.0 m/s toward the center of the circle• P1.2: 8.94 m/s toward the center of Earth• P1.3: Yes. a = 5.80g