Chapter 7: Momentum, Impulse, & Collosion

Use this studyguide to better prepare for the test!

Momentum

product of an object’s mass and velocity

*An object with a lot of momentum is HARD TO STOP*

Momentum (Must Know)…

Symbol: [p]

Formula: p=mv [mass x velocity]

SI Unit: kg, m/s

[Vector Quantity]

Momentum has direction regardless because…

the vector points in the same direction as velocity vector

*If direction and velocity change, momentum will change too*

Due to the vector nature of momentum, the total momentum can be either?

positive, negative, or zero

Total Momentum Formula

P total= P1 + P2 + ….

The change in momentum depends on?

the FORCE and the length of TIME

Impulse (Must Know)…

change in momentum of the object

Symbol: [J]

Formula: J= FxT [force x time]

If the change in momentum occurs over a long period of time, the force of the impact is?

SMALL

If the change in momentum occurs over a short period of time, the force of the impact is?

LARGER

The larger impact time reduces the force of impact does what?

decreases the decleration

For the Force/Time graph, area under the curve represents?

the impulse

For the Force/Time graph, damage is less if the impulse is?

spread over time

Conservation of Momentum

momentum before an event = momentum after an event

*Momentum in this state cannot be CREATED or DESTROYED*

Collision

an event where momentum or kinetic energy transfers from one object to another

In-elastic Collision

meaning “NO STICK” together

*MOMENTUM IS CONSERVED / KINETIC IS NOT CONSERVED*

In-elastic Collision Formula

(m1v1) + (m2v2) = (m1+m2) vf

(NOT STICKING TOGETHER)

Elastic Collision

meaning “bounce apart” or “STICK” together

*MOMENTUM CONSERVED / KINETIC CONSERVED*

(STICKING TOGETHER)

Changing the Ball Momentum Formula

Pfinal - Pinitial

Force

F= p/t [momentum / time]