What is momentum?
The sum of mass and velocity: p = m + v
The product of mass and velocity: p = m × v
The ratio of mass and velocity: p = m ÷ v
What is the unit of momentum?
Newtons per kilogram (N/kg)
Kilogram metres per second (kg m/s)
Newtons per metre (N/m)
What is the momentum of a 15 kg dog running at 4 m/s?
3.25 kg m/s
19 kg m/s
60 kg m/s
What does conservation of momentum mean?
Total momentum before is equal to total momentum after
Total momentum must decrease after a collision
All objects must start with some momentum
What is the momentum of a system at rest?
Infinite
1 kg m/s
0 kg m/s
What does mv - mu represent?
Initial momentum
Final momentum
Change in momentum
What does rate of change mean?
Total amount of change
Average change
Change per unit time
Which equation correctly links force and change of momentum?
F = (mv-mu) ÷ t
F = t ÷ (mv-mu)
F = (mv-mu) × t
Which car safety feature will not reduce the rate of change of momentum?
Roll cage
Airbag
Crumple zone
How do seatbelts and airbags reduce forces in a collision?
They increase collision time, which increases the rate of change of momentum
They increase collision time, which reduces the rate of change of momentum
They decrease collision time, which reduces the rate of change of momentum