Impulse Examples in Physics

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

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 product of force and time interval, equal to the resulting change in an object's momentum.

A big push for a short time or a small push for a long time can have the same effect.

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: Impulse equals change in momentum — it quantifies how force applied over time changes motion.

Common stuck point: Impulse equals the area under a force-time graph, not just force times a single moment.

Sense of Study hint: When solving an impulse problem, first determine whether you know the force and time interval or the change in momentum. Then use J = F\Delta t or J = \Delta p = m\Delta v depending on what is given. Finally, remember that extending the time of impact reduces the peak force for the same impulse.

Worked Examples

Example 1

easy
A force of 200 \text{ N} acts on a ball for 0.05 \text{ s}. What is the impulse delivered to the ball?

Solution

  1. 1
    Recall the impulse formula: J = F \Delta t, where F is the applied force and \Delta t is the time interval.
  2. 2
    Identify the given values: F = 200 \text{ N}, \Delta t = 0.05 \text{ s}.
  3. 3
    Substitute and calculate: J = 200 \times 0.05 = 10 \text{ N s}

Answer

J = 10 \text{ N s}
Impulse is the product of force and the time interval over which it acts. It equals the change in momentum of the object.

Example 2

medium
A 0.15 \text{ kg} baseball moving at 40 \text{ m/s} is hit by a bat and reverses direction at 50 \text{ m/s}. What impulse did the bat deliver?

Practice Problems

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

Example 1

medium
A 60 \text{ kg} person jumps and lands on the ground, changing velocity from -4 \text{ m/s} (downward) to 0 \text{ m/s} in 0.5 \text{ s}. What average force does the ground exert?

Example 2

medium
A 0.20 \text{ kg} hockey puck moves at 3 \text{ m/s} east, then is struck and moves at 7 \text{ m/s} west. What impulse was delivered to the puck?
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Background Knowledge

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

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