5.9.1 Momentum

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Momentum: All moving objects have momentum. If an object is not moving, the momentum is zero.

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Formula

p = m \times v

Momentum (kg m/s) = mass (kg) × velocity (m/s)

Where $p$ is the momentum in kilograms meters per second $kgms^-1$ , $m$ is the mass in kilograms (kg), and ( $v$ ) is the velocity in meters per second $ms^-1$ .

Conservation of Momentum

In a closed system, the total momentum before an event is equal to the total momentum after an event.

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Example: The backwards momentum of a cannon is equal to the forward momentum of the cannonball.

Momentum is always conserved in a collision or explosion (where there are no external forces like friction, air resistance, electrostatic attraction, etc.).
In collisions: $\text{total momentum before} = \text{total momentum after}$

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Example: Two marbles colliding; each will have momentum before and after the collision.

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Remember, momentum is a vector.

Changes in Momentum (Physics Only)

Newton's Second Law

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Force is equal to the rate of change of momentum.

\text{Force} = \frac{\text{change in momentum}}{\text{time}}\ F = \frac{(mv - mu)}{t}

Where $F$ is the force, $mv$ is the final momentum, $mu$ is the initial momentum, and $t$ is the time.

Momentum Simplified Revision Notes for GCSE AQA Physics Combined Science

5.9.1 Momentum

Conservation of Momentum

Changes in Momentum (Physics Only)

Newton's Second Law

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