Momentum and Impulse

Momentum(p)-

Momentum and Impulse

Momentum- Newton referred to it as the quantity of motion

Momentum and Impulse

Momentum- It is defined mathematically as the product of mass and velocity of an object

Momentum and Impulse

Momentum-

p mv

Momentum and Impulse

Momentum is a vector quantity. The momentum vector points in the same direction as the velocity vector.

Momentum and Impulse

Example – What is the momentum of a puck with a mass of 2.0kg sliding to the right on the x axis at 2.0m/s

Momentum and Impulse

Example –

2.0 2.0 4.0m m

P mv kg x kg xs s

Momentum and Impulse

The momentum of a system of objects is equal to the vector sum of the momenta of the individual objects.

Momentum and Impulse

Example – What is the momentum of a system consisting of puck with a mass of 2.0kg sliding to the right along the x axis at 2m/s, and another puck with a mass of 1.0kg sliding to the left along the x axis at 5.0m/s

Momentum and ImpulseExample –

1 1 2 2

2.0 2.0 1.0 5.0

1.0

P m v m v

m mkg x kg x

s s

mkg xs

Momentum and ImpulseImpulse (J) is defined as the change in momentum

f iJ p p p

Momentum and ImpulseImpulse (J) is also equal to the average force acting on an object multiplied by the time interval during which it is acting.

J Ft

Momentum and ImpulseExample – a ball with a mass of 0.50kg and moving with a velocity of 10.0m/s strikes a wall, and bounces off in the opposite direction at 5.0 m/s. Consider the initial velocity to be positive.a. Calculate the impulse given to the ballb. If the contact with the wall lasted for 0.01s

what was the magnitude of the average force exerted on the ball?

Momentum and ImpulseExamplea.

0.50 0.5 5.0 10.0 7.5f i

m m kg mJ p v v kg

s s s

Momentum and ImpulseExamplea.

The negative sign indicates that the force acted in the direction opposing the original motion

7.5 0.01

7.5750

0.01

kg mJ p Ft F s

skg msF Ns

Momentum and ImpulseSummary:

f i

momentum p mv

impulse J p m v m v v Ft