Energy is transmitted at an average rate of P_{avg,1} by a wave of frequency f_{1}
on a string with tension t_{1}. What is the new
average energy transmission rate
P_{avg,2} in terms of P_{avg,1},

a. if the tension of the string is increased to t_{2 }
= 4t_{1},
and

b. if, instead, the frequency of the wave is decreased to f_{2
}= f_{1}/2?

Example 2

a. The rate of energy transferred = W

Answer

b. The average power transmitted by the
wave is

The average power is reduced by a factor of four.

the rate of energy transmitted is quarter the original value.

a. The average power transmitted by the wave is

b. The rate of energy transferred = W

Therefore, the power transmitted doubles.