How is power related to energy?

Power is the rate at which energy is transferred or used.

Power and energy are closely related concepts in physics. Energy is the ability to do work, while power is the rate at which work is done or energy is transferred. Mathematically, power is defined as the amount of energy transferred or used per unit time.

The SI unit of power is the watt (W), which is defined as one joule (J) of energy transferred per second (s). Therefore, power can be calculated using the formula:

Power = Energy transferred / Time taken

P = E / t

For example, if a 100 W light bulb is turned on for 10 seconds, the energy used can be calculated as:

Energy = Power x Time

E = P x t

E = 100 W x 10 s

E = 1000 J

Similarly, if a car engine produces 200 horsepower (hp) of power, this can be converted to watts using the conversion factor:

1 hp = 746 W

Therefore, the power output of the car engine in watts is:

Power = 200 hp x 746 W/hp

Power = 149,200 W

In summary, power and energy are related concepts in physics, with power being the rate at which energy is transferred or used. The SI unit of power is the watt, and power can be calculated using the formula P = E / t.