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Physics: 2 > Momentum and Collisions > Flashcards

Flashcards in Momentum and Collisions Deck (13)
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1

What is the equation for momentum?

Momentum = mass x velocity

2

What is the sign for momentum?

p

3

Momentum is a property of what?

Moving objects

4

What happens to momentum as the mass is increased?

The momentum increases too

5

What happens to momentum when the velocity increases?

The momentum increases too

6

What does it mean that momentum is a 'vector' quantity?

It measures size and direction 

(like velocity, but not speed)

7

What is the formula triangle for momentum? 

8

Write the units in the momentum equation

momentum (kgm/s) = mass (kg) x velocity (m/s)

9

What is the equation for momentum before and after a collision? (in a closed system)

Momentum before = Momentum after

10

What is the fact that momentum after a collision is equal to the momentum before the collision known as?

Conservation of Momentum

11

State the steps in answering a momentum question in a collision (asking for the velocity)

1. Choose which direction is positive (e.g. to the right)

2. Work out total momentum before collsion by adding the momentum of the 2 colliding objects

3. Add the masses of the objects, and arrange in this formula:

total momentum = combined masses x velocity

4. you should be able to rearrange the equation to get the velocity (as you have the figures of the underlined parts)

12

Try a practice question:

Two ice hockey players are skating towards the puck. Player A has a mass of 100kg and is travelling right at 6 m/s. Player B has a mass of 80kg and is travelling left at 9m/s.

Calculate the momentum of:

a) Player A

b) Player B

momentum = mass x velocity

right = positive

a) Player A: 100 kg x 6 m/s = 600 kgm/s to the right

b) Player B: 80kg x -9 m/s = 720 kgm/s to the left ( -720 kgm/s )

13

The second part to the question:

(Player A's momentum = 600 kgm/s, mass = 100 kg, and Player B's momentum = -720 kgm/s, mass = 80 kg)

The two players collide and become joined together.

a) Calculate the speed of the 2 joined players just after the collision

b) State the direction they move

momentum = mass x velocity

right still = positive (although you could change this)

a) 600 kgm/s + - 720 kgm/s = -120

-120 = (100 + 80) x v

-120 = 180 x v

-120 / 180 = v = -0.666... = -0.67 m/s

b) They move to the left