Power

• Power measures how quickly energy is used or generated.
• In physics, power is defined as the rate at which work is done or the rate at which energy is transferred or converted. It quantifies how quickly energy is used or generated within a system.
• When work is done on an object, energy is transferred to or from it, and power measures how rapidly this transfer occurs.
• Essentially, power describes the efficiency or speed of energy conversion processes.
• The equation used to measure power is P = W/t, where P is power, W is work, and t is time.
• Energy is measured in joules, while power is measured in watts or joules per second.

Here is an example:

• If you lift a 10 kg object one meter in two seconds, the work done is W = Fd = mg*d = 10 kg * 9.81 m/s^2 * 1 m = 98.1 J, where F is the force applied, d is the distance lifted, m is the mass of the object, and g is the acceleration due to gravity.
• The power used to lift the object is then P = W/t = 98.1 J / 2 s = 49.05 W.
• This means that you are transferring energy to the object at a rate of 49.05 J/s, or 49.05 watts.

• Horsepower is another unit of power where one horsepower is equal to 745.7 watts
• One horsepower is equivalent to the power required to lift 550 pounds of weight at a rate of one foot per second.
• James Watt, a Scottish engineer, adopted the term in the late 18th century to compare the output of steam engines with the power of draft horses. It was later expanded to include the output power of other types of piston engines, turbines, electric motors, and other machinery.