Some object is moving back and forth in harmonic motion. Where is the
acceleration of that object greatest?
at the midpoint of the motion
at the end points of the motion
same value at every point
Consider a mass m hanging on a spring.
We pull the weight downward and
then release it so that it oscillates up and down. If we repeat this
on the moon with the same weight and the same spring, the frequency of the
oscillation will be
larger,
smaller, or
the same.
Ralph asked me a question about pendulums. In the textbook, the period
T
of a pendulum depends on its length L
and on the acceleration of gravity g,
but does not depend on its mass. Ralph thinks that heavier pendulums
should swing with a longer period. After all, if he puts a heavier weight
on the end of the spring, it oscillates up and down with a longer period.
Can you help Ralph understand this?
Suppose that you are approaching a yellow light. If you go fast enough,
you can use the Doppler effect to change the yellow light to
red or
blue.
Note: Red light has a longer wavelength than yellow,
and blue light has a shorter wavelength than yellow.
You hear a sonic boom
when an aircraft first exceeds the speed
of sound ("breaks the sound barrier") or
whenever an aircraft flies overhead faster
than the speed of sound.