Grandfather Clocks on the Moon

Imagine you have a grandfather clock on the moon. On earth the Pendulum swings in a regular motion to keep accurate time. What is the period of the swing on the earth and what is it on the moon?

 

 

 

 

In solving this problem we must make several major assumptions. First we assume that the pendulum is massless except for the bob, that it rotates through a frictionless point. Because the angle of rotation is so small we also assume simple harmonic motion.

The period of a pendulum is dependent on gravity on the earth and the length of the rod. The period of a mass undergoing simple harmonic motion is:

T = 2(Pi)((L/g)^1/2)

T = 2(3.14)((1/9.8)^1/2)

T = 2 seconds

On the moon the period is much different:

T = 2(3.14)((1/1.6)^1/2)

T = 4.97 seconds

On the moon the clock would not keep accurate time because the period is much longer for a simple pendulum in lower gravity.

 

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