as listed on the equation sheet!
The Compound Pendulum
The basic approach to pendulums detailed above refers to “simple” pendulums for which the dimensions
of the hanging mass are irrelevant. If the hanging mass has a size approaching the length of the string, the
period of this “compound” pendulum is
where I is the rotational inertia of the hanging mass, m is the hanging mass, and d is the distance from the
center of mass to the top of the string. Only use this equation if you haveto. The vast majority of physics C
pendulums involve long strings and masses small enough to make the simple pendulum approximation
valid. After all, for a “point” mass on the end of the string, the rotational inertia is I = mL 2 , meaning that
even the compound formula reduces to
Practice Problems
1 . A basketball player dribbles the ball so that it bounces regularly, twice per second. Is this ball in
simple harmonic motion? Explain.Multiple Choice:
2 . A pendulum has a period of 5 seconds on Earth. On Jupiter, where g 30 m/s^2 , the period of this
pendulum would be closest to
(A) 1 s
(B) 3 s
(C) 5 s
(D) 8 s
(E) 15 s3 . A pendulum and a mass on a spring are designed to vibrate with the same period T . These devices
are taken onto the Space Shuttle in orbit. What is the period of each on the Space Shuttle?