B. Energy
A power company charges its customers for electricity based upon B. Energy.
<h3>
Explanation:</h3>
Kilo-watt Hours (kWh) is the unit that measures the electricity consumption of customers. Since Power is defined as the rate at which electrical energy is transferred by an electrical circuit per unit time,

If energy is transmitted at a constant rate over a period of time, the total energy in kilowatt hours is the product of power in kilowatts(kW) and time in hours (h)

Answer: The correct option is Option b.
Explanation:
Power is defined as the rate of work done by an object.
Mathematically,
.....(1)
And work done is the product of force exerted on the object times the displacement covered by that object.
Mathematically,

Putting this value in above equation, we get:

where,
P = power = ?W
F = Force exerted = 10N
s = Displacement = 400cm = 4m (Conversion factor: 1m = 100 cm)
t = Time taken = 8s
Putting values in above equation, we get

Hence, the correct option is Option b.
The correct answer is:
<span>C) The actual frequency of the siren does not change despite appearances.
In fact, Bob will observe an increase in the apparent frequency as the emergency vehicle approaches him, while Jill will observe a decrease in the apparent frequency as the emergency vehicle moves away from him, because of the Doppler effect (the relative velocity between the observer and the source of the sound is changing), but this effect involves the apparent frequency, while the real frequency of the siren will remain the same.</span>
C.
Because it’s falling it has acceleration in the y direction. If you have acceleration, you usually also have velocity, and since kinetic energy is KE= Mv^2 you know you have it. It also has potential energy because it has some height to it, and PE= Mgh.