Work Examples in Physics

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Work.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Physics.

Concept Recap

The transfer of energy that occurs when a force causes an object to move through a distance in the direction of the force, calculated as the dot product of force and displacement vectors.

Energy transferred by pushing something through space — force and displacement must both be present.

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: No displacement means no work is done, even if a large force is applied.

Common stuck point: Holding a heavy bag still does zero work (no distance), even though you get tired.

Sense of Study hint: When solving a work problem, first identify the force and the displacement of the object. Then find the angle \theta between the force direction and the displacement direction. Finally, calculate W = Fd\cos\theta — if the force is perpendicular to the displacement, the work is zero.

Worked Examples

Example 1

easy
A person pushes a box with a force of 50 \text{ N} over a distance of 10 \text{ m} in the direction of the force. How much work is done?

Solution

  1. 1
    Because the force is in the same direction as the displacement, use W = Fd.
  2. 2
    Substitute the values: W = 50 \times 10.
  3. 3
    W = 500 \text{ J}

Answer

W = 500 \text{ J}
Work is done when a force causes displacement. When force and displacement are in the same direction, work equals force times distance.

Example 2

medium
A person pulls a sled with 100 \text{ N} at 30° above the horizontal for 20 \text{ m}. How much work is done?

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

medium
A 5 \text{ kg} box is lifted 3 \text{ m} vertically at constant speed. How much work is done by the lifting force? Use g = 9.8 \text{ m/s}^2.

Example 2

hard
A child pushes a 20 \text{ kg} crate 8 \text{ m} across a floor with a 60 \text{ N} horizontal force. Friction exerts 40 \text{ N} opposing the motion. What is the net work done on the crate?
← Back to Work Formula Explained Practice Mode

Background Knowledge

These ideas may be useful before you work through the harder examples.

forceenergy