# 1 Momentum, N3L and suvat Flashcards

What effect does a cushion on the inside of a helmet have on the impact force felt by a cyclist if they collide with a windscreen?

- cushion increases the collision time
- F = (change in momentum)/ time
- Larger collision time for the same change in momentum
- decreases the impact force
- Less force, less injury

What is different about N3L pair forces?

- they act in different directions
- they act on different objects

Is momentum a vector quantity?

Yes- it has both magnitude and direction

Define momentum

The property an object has due to its mass and velocity. It is the product of its mass and velocity

mass in motion!!!

Name the N3L pair force for the force named below

The __water__ pushes up and forward on the __swimmer__

What effect does making a hammer of hard steel have on the impact force on a nail?

- hard steel hammer decreases the collision time
- F = (change in momentum)/ time
- smaller collision time for the same change in momentum
- increases the impact force
- more force, easier to drive in nail

Use the conservation of momentum to create a equation for the collision below

p_{before }= p_{after}

[0.01 kg x 300m/s] + [0] = [(0.01 kg + 1.99kg) x v]

- Note the velocity of the block before is 0m/s*
- After the bullet is in the block and the total mass of the system is 2.00 kg*

Explain why the velocity of the cart decreases after the mass is dropped onto it.

Momentum is conserved

p before = p after

m_{before} x v_{before} =m_{after} x v_{after}

m_{ }V = M v

If the mass of the system increases after the collsion the velocity must decrease to keep momentum the same.

Define force in terms of momentum

Force = change of momentum / time

What does the area of a force-time graph represent?

F t = change in momentum

This is called impulse

The area of a force-time graph is the impulse

The same object undergoes a change in motion indicated as Case A and Case B.

In which case is the change in momentum the greatest?

Case A- Since mass is the same we can look at the change in velocity.

The change in velocity is found by using

(v-u)

(-3 m/s) - (5m/s)

= -8m/s

If a person on a skateboard pushes on a wall. Name the N3L pair force of….

__Persons’__ force on __wall__

__Walls’__ force on __person__

What is the relationship between momentum, mass and velocity?

p=mv

Momentum = mass x velocity

When a person runs they exert a back and downwards force on the road surface. Name the N3L pair of this force….

__Runner__ pushes back and down on the __road__

__Road__ pushed up forwards and up on the __runner__

What is the unit for momentum?

kgm/s