3.4.1.6 Momentum

Question 1

What is the formula for linear momentum?

Answer 1

p = mv
(v as in linear velocity)

Question 2

What is the principle of linear momentum?

Answer 2

Assuming no external forces act, linear momentum is always conserved;
total linear momentum of objects before they collide = total linear momentum of objects after they collide

Question 3

What is an elastic collision?

Answer 3

One where momentum is conserved and kinetic energy is conserved i.e. no energy is dissipated as heat or sound

Question 4

What is the formula for the rate of change of momentum?

Answer 4

F = delta mv / delta t

Question 5

What is the formula for the change in momentum?

Answer 5

delta mv = mv - mu

Question 6

What is an impulse?

Answer 6

The product of force and time; equal to the change in momentum of that body

Question 7

What is the formula for impulse?

Answer 7

F delta t = delta mv

Question 8

What type of transport design helps reduce impact forces?

Answer 8

Crumple zones
Seat belts
Air bags

Question 9

Describe how crumple zones work

Answer 9

Parts of the front and back of the car crumple up and deform plastically, causing the car to take longer to stop, increasing impact time and decreasing the force on the passengers

Question 10

Describe how seat belts work

Answer 10

Stretch slightly, increasing the time taken for the wearer to stop, reducing the force acting on the chest

Question 11

Describe how air bags work

Answer 11

Slow down passengers gradually and prevent them from hitting hard surfaces inside the car