Momentum Examples in Physics

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

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 an object's mass and velocity, representing the quantity of motion it carries.

How hard it is to stop something moving. Heavy and fast = lots of momentum.

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: Momentum is a vector quantity — it has both magnitude and direction, just like velocity.

Common stuck point: Momentum is not the same as kinetic energy—they have different formulas and conservation rules.

Sense of Study hint: When solving a momentum problem, first identify the mass and velocity of each object involved. Then calculate momentum using p = mv for each object, keeping track of direction with signs. Finally, apply conservation of momentum (p_{\text{before}} = p_{\text{after}}) if the system is closed.

Worked Examples

Example 1

easy
A 2 \text{ kg} ball moves at 5 \text{ m/s}. What is its momentum?

Solution

  1. 1
    Recall the momentum formula: p = mv, where m is mass and v is velocity.
  2. 2
    Identify the given values: m = 2 \text{ kg}, v = 5 \text{ m/s}.
  3. 3
    Substitute and calculate: p = 2 \times 5 = 10 \text{ kg m/s}

Answer

p = 10 \text{ kg m/s}
Momentum is the product of mass and velocity. It is a vector quantity, meaning it has both magnitude and direction.

Example 2

medium
A 1500 \text{ kg} car moving at 20 \text{ m/s} and a 0.05 \text{ kg} bullet moving at 600 \text{ m/s}. Which has greater momentum?

Practice Problems

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

Example 1

easy
What velocity must a 0.5 \text{ kg} ball have to possess a momentum of 15 \text{ kg m/s}?

Example 2

medium
A 1200 \text{ kg} car moves east at 25 \text{ m/s} while a 1000 \text{ kg} car moves west at 10 \text{ m/s}. What is the total momentum of the two-car system?
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Background Knowledge

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

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