Friday, October 12, 2001

Announcements: Chapter 7: Circular Motion and the Law of Gravity

Example 7.7:  What is the angular speed of the yo-yo in Fig. 7.10 if the string is 40 cm long?  What is the tension in the string?  If the string is shortened, how do the speed, tension, and acceleration change?

Whirlygig demo:  Why does the spinning mass speed up as the string gets shorter?  How will the angular speed change as the radius is doubled?

Bucket of nails:  How fast do I need to swing the bucket in a vertical circle to keep the nails from falling out?

The Texas Motor Speedway has 750-ft radius turns that are banked at 24 degrees.  For what speed are these turns designed?  What coefficient of friction is needed to keep a race car from skidding when v = 200 mph?  What G-force does the driver experience at this speed?

Example 7.14:  Find the altitude required for a satellite to remain in geosynchronous orbit.

Assignments: