Linear Momentum

Level 3: Lesson 1

Siobhan Rigby

A little about me: Siobhan

Rigby

My Family is from Ireland

I grew up in New Orleans

until Hurricane Katrina

Then I moved to Richmond, Virginia

and I go to school at MIT in Boston

I am in my 3rd year, studying Mechanical

Engineering with Biomedical Devices

I play Field Hockey at

MIT

I love to sew, tango, run, hang out

with friends and explore!

Concept question

Use the paper provided and answer A,B, C, or D

Which is the best football team? A B

C D

Which is the best

Movie? A B

C D

What is momentum?

Equation

The linear momentum p of an object of

mass m with a velocity of v is

It is a vector and points in the same direction as

the velocity vector.

vmp

What is a vector?

A. It has a direction

B. It has magnitude

C. It is an American candy

D. A and B are both correct

Different vectors in Physics

Velocity

Acceleration

Momentum

All in common: Direction and magnitude

Momentum Vector

In same direction as the velocity vector used to calculate it

It is directly proportional in magnitude to the velocity vector

If the velocity doubles- the momentum doubles

Also directly proportional in magnitude to mass

If the mass doubles- the momentum doubles

Example 1: Which has the most

momentum?

A. A bicycle that is going 15 m/s and weighs 10kg

B. A car that is going 30m/s and weighs 1500kg

C. A tank that is going 5m/s and weighs 60000kg

D. A bullet that is going 350m/s and weighs 0,5kg

Determine the Momentum of . . .

A. 60kg American football player moving east at

9m/s

B. 1000kg car moving north at 20 m/s

C. 40kg football player moving south at 2m/s

A Lamborghini Gallardo has 20 000

units of momentum. What would be

the new momentum if. . .

A. The velocity was doubled (x2)

B. The velocity was tripled (x3)

C. The mass was doubled (x2) (with more

passengers)

D. Both the velocity and mass was doubled

Conservation of

Momentum

What happens when things fall apart?

What happens when objects collide?

What happens when cars hit each other? Can they still have

momentum?

Power of the

conservation of

momentum:

Mythbusters

https://www.youtube.com/watch?v=BiLq5Gnpo8Q

Conservation of Momentum

This means that the vector sum of the momenta

before collision is equal to the vector sum of the

momenta of the particles afterwards

What happens in

Space? (no gravity)

There is still

conservation of

momentum!

https://www.youtube.com/watch?v=4IYDb6K5UF8