Given :
A rope 6m long is fixed at one end, the other end is attached to a light string so that it is free to move.
The speed of waves on the rope is 18 m/s.
To Find :
The frequency of the second harmonic.
Solution :
We know, for second harmonic wave :
Wavelength = Length of rope

Now, we know frequency is given by :

Therefore, the frequency of the second harmonic is 3 s⁻¹.
Answer:
<em>300 W</em>
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Explanation:
power of each bulb P = 75 W
voltage in the circuit = 120 V
we know that electrical power P = IV ....1
and V = IR
we can also say that I = V/R
substituting for I in equation 1, we have
P =
....2
The total total power in the circuit = 75 x 2 = 150 W
from equation 2, we have
150 = 
R =
= 96 Ω this is the resistance of the whole circuit.
This resistance is due to the two light bulbs, for each light bulb since they are arranged in series
R = 96/2 = 48 Ω
From P =
for each light bulb, power is
P =
= <em>300 W</em>
This is an example of kinetic to potential because the water is moving, pushing a turbine (Kinetic) and the turbine converts the energy to potential energy.
Potential energy , hope this helps :)