Momentum and Impulse
A New Way to Measure Motion
Momentum
Momentum is defined as . It combines mass and velocity, so a heavy fast object has more momentum than a light slow one.
Impulse
Impulse is force applied over time, and it changes momentum: . For constant force, .
Why impulse matters
A small force acting for a long time can change momentum as much as a large force acting briefly.
Conservation of momentum
If no external net force acts on a system, total momentum stays constant. This is extremely useful in collisions and explosions.
What is momentum?
Momentum is mass times velocity.
Correct answer:
What does impulse equal?
Impulse is the quantity that changes momentum.
Correct answer: Change in momentum
Momentum vs. impulse
Momentum
- State of motion
- Usually conserved in isolated systems
Impulse
- Change caused by force over time
- Explains how momentum changes
Momentum problem strategy
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Step 1: Define the system clearly.
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Step 2: Check whether external forces can be neglected.
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Step 3: Write initial and final total momentum.
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Step 4: Use conservation of momentum if appropriate.