Momentum

If an object is not moving what’s it momentum

It’s 0

How to calculate momentum

Momentum(kg/m²)= Mass X velocity(m/s)

What is the Conservation of momentum

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

Describe how momentum works when car hits car infront

-Van has momentum at a forward direction

-Stationary car has no momentum as it’s not moving

-The Van now collides with the car so both Van and car move at lower velocity than initial velocity of Van

-The total momentum of Van and car together is now the same as the initial momentum of the Van itself

Momentum before = Momentum after l

A van with a mass of 2000kg is travelling at 30m/s it collides with a stationary car with mass 800kg. Both van and car continue moving together

Calculate velocity of the van and car together

Momentum of Van = 2000X 30 =60,000

Momentum of car= 0 as stationary

So total momentum before collision with car and van is 60,000 kg m/s

Momentum is always conserved so momentum after collision is 60,0000 kg m/s

Velocity after collision for both van and car = 60,000/2800=21.429 m/s

How can you calculate force involving mass change in velocity and time (Given in exam)

Force(N) = Mass(kg) X change in velocity(m/s)/ change in time(s)

OR

Change in momentum/time

Force= (100 X 30)/1=3,000 N

Name five safety devices to slow down momentum

-Airbags

-Seatbelts

-Crash mat

-Bike helmet

-cushioned surface for playgrounds

These all slow down momentum to reduce force acting and reducing risk of injury