Lesson 5: Work, Power, and Energy
Understanding Work, Power, and Energy
Work is done when a force moves an object over a certain distance. Power is the rate at which work is done. Energy is the ability to do work.
Work is calculated as the product of the force and the distance over which it acts: W = Fd.
Power is the rate at which work is done: P = W/t.
Energy comes in various forms, including kinetic energy (energy of motion) and potential energy (stored energy).
Example Problems
Example problem:
A 10 kg box is speeding up at a rate of 2 m/s² for 10 seconds. Find the work applied to the box.
Solution:
Force = Mass * Acceleration
= 10 kg * 2 m/s²
= 20 N
Distance = 0.5 * Acceleration * Time²
= 0.5 * 2 m/s² * (10 s)²
= 100 m
Work = Force * Distance
= 20 N * 100 m
= 2000 J
Another example:
A light bulb has a power rating of 60 watts. How much work does it do in 10 seconds?
Solution:
Power = Work / Time
Work = Power * Time
= 60 W * 10 s
= 600 J