5.7 Momentum

What is the equation that defines momentum?

p = mv

What are the units for momentum? (written out)

kilograms metre per second (kg m/s)

Is momentum a scalar or vector quantity?

Vector

In a closed system, the total momentum before an event is ________ to the total momentum after the event. What is this called?

• equal

• conservation of momentum

What is a closed system?

A system where no external forces act.

How does conservation of momentum apply to collisions?

The total momentum of all objects before they collide is equal to their total momentum after they collide.

How does conservation of momentum apply to explosions?

When objects push away from each other, the total momentum is conserved.

Which equation is a combination of 'F = ma' and 'a = (v - u) / t'?

F = (m∆v) / ∆t

When a _________ acts on an object that is moving, or able to move, a change in ____________ occurs.

• force

• momentum

What is change of momentum shown as in equations?

m∆v

How do safety features like airbags and crash mats work in terms of momentum change?

They increase the time taken for a person’s momentum to change during an impact, which reduces the force exerted on them.