Explanation:
We know that kWh is a commercial unit of energy.
Also, 1 Joule = 1 watt × 1 seconds

Since ,1 h = 3600 s and 1kW = 1000 W

So, the relation is : 
1 watt is defined as the power of an appliance when the energy is transferred at a rate of 1 Joule per second.
Answer:

Explanation:
As we know that if the block will complete the circular motion of the path then the speed at the bottom most part of the path must be equal to

now we know that
velocity at the bottom of the path is due to conversion of potential energy to kinetic energy
so we can say it is given as


now we have


Answer:
(a)
= 0.22 W
(b)
= 0.056 W
Explanation:
given information:
the mass of piano wire, m = 3.00 g = 0.003 kg
tension, F = 25 N
length, l = 80 cm = 0.8 m
frequency, f = 120 Hz
amplitude, A = 1.6 mm = 0.0016 m
(a) the average power carried by the wave, 
=
(√μF)ω²A²
where,
ω = 2πf = 2π120 = 754
μ = 
= 
= 0.00375 kg/m
thus,
=
(√(0.00375)(25))(754)²(0.0016)²
= 0.22 W
(b) What happens to the average power if the wave amplitude is halved.
based on the equation above, we know that the average power is proportional to the square amplitude. therefore


= 
= 0.056 W
Can't say for sure but I think it's a) or c)