Work & Energy
Physics: AQA A Level, topic 4.1.21
Work Done
Moving something or heating something up requires energy. Work done is the amount of energy transferred.
Work done in a straight line
- Work done is measured in Joules (J).
- It is given by the equation:
- Work done = force applied × distance travelled
- W = F × s
Work done at an angle
- Sometimes the force, F, applied to an object is at an angle, θ, to the direction of motion.
- In this case, we only consider the component of the force which is in the same direction as the direction of motion.
- This gives us a more general formula for work done:
- W = F s cos θ
- If θ = 0, then cosθ = 1, and we return to the original equation W = F × s.
Test yourself on Work & Energy
What is the equation for work done?
What is the work done by a force perpendicular to the movement?
How can we find the work done from a force-displacement graph?