Unit 5: Momentum

State the definition of momentum

A measure of the quantity of motion an object has

State the definition of force

The rate of change in momentum

State the definition of impulse

The product of time and force / the total change in momentum

Name the factors that can influence momentum

Velocity and mass

Why should cars stick together in a crash?

Cars during a car crash will experience less force sticking together than bouncing back. This is because the act of bouncing back requires a change in direction, which otherwise increases total velocity change. Momentum is dependent on both mass and velocity, thus higher velocity changes lead to higher changes in momentum. A higher change in momentum leads to increased force.

Explain the difference in direction between change in momentum, impulse, force and final and initial momentum

Impulse, change in momentum, and force will always face in the same direction whereas initial and final momentum can differ.

How do you calculate the final momentum when initial velocity is 0?

Find the change in momentum.

How do you reduce force when change in momentum is constant?

You increase time.

To increase impulse...

you must increase either force or time or both.

Describe a scenario where force is reduced by extending time

To reduce the force applied on a human as they land from a jump, the knees bend to extend time.

What is the symbol of impulse?

J

Name the SI unit(s) for impulse and momentum

Momentum and impulse can be measured in Ns or kgms^-1

State the type of quantities for impulse and momentum

Both are vector quantities.