MomentumMomentum is what Newton called the

“quantity of motion” of an object.

MomentumThe momentum of an object:Depends on the object’s mass.

Momentum is directly proportional to mass.

Depends on the object’s velocity. Momentum is directly proportional to

velocity.

MomentumAll objects have mass; so if an object is

moving, then it has momentum - it has its mass in motion.

The amount of momentum which an object has is dependent upon two variables: how much matter is moving? how fast the matter is moving?

• Momentum: "mass in motion”• Equation: p = m x v• Unit: kg*m/s

Where;

p = momentum

m = Mass

v = Velocity

Momentum (p) In symbols:

Transcription Triangle

p = mv

m = ?

v = ?

p

m v

MomentumMomentum is a vector quantity.Common units of momentum: kg m/s

Momentum Questions

2. A car possesses 20,000 units of momentum. What would be the car's new momentum if ...

a.) its velocity were doubled b.) its mass were doubledc.) both its velocity and mass were

doubled

p = 40,000 units

p = 40,000 units

p = 80,000 units

Ticket of UnderstandingWhat are the variables to calculate the

product of momentum?

What is the formula?

Momentum Questions 1. Determine the momentum of a ...

a.) 60 kg halfback moving eastward at 9 m/s.

b.) 1000 kg car moving northward at 20 m/s.

c.) 40 kg man moving southward at 2 m/s.

p = 540 kg*m/s, east

p = 20,000 kg*m/s, north

p = 80 kg*m/s, south

If the boulder and the boyhave the same momentum,will the boulder 1000 kg. crush the boy 35 kg.? EXPLAIN.

Hint, Hint, Hint:

 Think about the momentum formula!

p = mv

ImpulseThe impulse exerted on an object

depends on:The force acting on the object.

Impulse is directly proportional to force.The time that the force acts.

Impulse is directly proportional to time.

Impulse (I) In symbols:

I = Ft IF t

Impulse = change in momentum

F∆t = ∆p = ∆(mv)

F∆t = mvf - mvi

F∆t = m (vf – vi)

∆= Delta = Changef = finali = initial

Impulse

Impulse is a vector quantity.Common units of impulse: N s

Impulse & MomentumThe impulse exerted on an object

equals the object’s change in momentum.

Impulse & Momentum In symbols:

I = p

Conservation of MomentumSince impulse = change in

momentum, If no impulse is exerted on an object, the momentum of the

object will not change.

Conservation of Momentum

If no external forces act on a system, the total momentum of the system will

not change.

Such a system is called an “isolated system”.

Conservation of Momentum

Momentum is conserved in every isolated system.

Conservation of MomentumAnother way to think about it is:

Internal forces can never change the

total momentum of a system.

Conservation of Momentum In practice, for any event in an isolated

system:

Momentumafter = Momentumbefore

The End.