Question

Water waves are hitting against a boat. If the frequency of water waves is reduced to one-third of the original frequency, what happens to the energy transferred to the boat?(1 point)

The energy transferred to the boat is reduced to one-half of the original energy.

The energy transferred to the boat is increased to nine times the original energy

The energy transferred to the boat is increased to four times the original energy.

The energy transferred to the boat is reduced to one-third of the original energy.
Two sound waves (wave X and wave Y) are moving through a medium at the same speed. If wave X has a greater frequency than wave Y, then wave X(1 point)

has a shorter wavelength.

has a longer wavelength.

has a lower amplitude.

has a greater amplitude.
Bill is making waves on a rope with one end attached to a wall. When he starts moving the rope quickly, the frequency of the waves created on the rope doubles. What happens to the energy that is transferred to the wall when the frequency of the waves doubles?(1 point)

The energy transferred to the wall is doubled.

The energy transferred to the wall is halved.

The energy transferred to the wall is tripled.

The energy transferred to the wall is quadrupled

Answer 1

1) The energy transferred to the boat is reduced to one-third of the original energy.
- If the amplitude (energy per wave) stays the same, halving the frequency reduces the number of waves hitting per time; energy per time (power) ∝ frequency, so reducing f to 1/3 reduces energy transferred per time to 1/3.

2) has a shorter wavelength.
- v = f λ, so for the same wave speed, larger f ⇒ smaller λ.

3) The energy transferred to the wall is doubled.
- If amplitude stays the same, doubling the frequency doubles the number of waves hitting the wall per unit time, so the energy transferred per time doubles.