Varying a pulse*
A long, taut string is attached to a distant wall (see figure). A demonstrator
moves her hand and creates a very small amplitude pulse that reaches the wall
in a time t0. A small red dot is painted on the string halfway
between the demonstrator's hand and the wall. For each item, state which of
the actions 1-10 listed below taken by itself will produce the desired
result. For each question, more than one answer may be correct, If
so, give them all.
How, if at all, can the demonstrator repeat the original experiment to produce:
- A pulse that takes a longer time to reach the wall.
- A pulse that is wider than the original pulse.
- A pulse that makes the red dot travel a further distance than in the original experiment.
- Move her hand more quickly (but still only up and down once and
still by the same amount)
- Move her hand more slowly (but still only up and down once and still
by the same amount).
- Move her hand a larger distance but up and down in the same amount
- Move her hand a smaller distance but up and down in the same amount
- Use a heavier string of the same length under the same tension.
- Use a lighter string of the same length under the same tension.
- Use a string of the same density, but decrease the tension.
- Use a string of the same density, but increase the tension.
- Put more force into the wave.
- Put less force into the wave.
* From the Wave Test by M. Wittmann
Page last modified
October 31, 2002: O30