Momentum is a vector quantityThat is defined as the product

Of an object’s mass and velocity.

p = mv

A 2250 kg pickup truck has a Velocity of 25 m/s to the east.

What is the momentum of The truck?

56250 kg m/s

A 21 kg child is riding on a 5.9 kgBike with a velocity of 4.5 m/s To the north west. What is the

Total momentum of the child & bikeTogether? Just the child? Just

The bike?

120 kg m/s 94 kg m/s 27 kg m/s

A change in momentum Takes force and time.

FΔt = Δpor

FΔt = mvf - mvi

The Impulse-Momentum Theorem

Impulse (for a constant externalForce) is the product of the

Force and the time over whichIt acts on an object.

FΔt is called the Impulse.

A 1400 kg car moving westward With a velocity of 15 m/s

Collides with a utility pole. It is thenBrought to a stop in 0.30s. Find

The magnitude of the force Exerted on the car during the

Collision.

7 X 104N

Stopping times and distances Depend on the impulse-

Momentum theorem.

A change in momentum over A longer time requires less force.

Angular momentum is the productOf a rotating object’s moment

Of inertia and angular Speed about the same axis.

L = Iω

Erica, 65kg, is spinning on a merry-Go-round that has a mass of 115kg,

And a radius of 2m. She walks From the edge to the center. If

The angular speed is initially 2 rad/sWhat is its angular speed when she

Reaches a point 0.5m from The center?

3.9 rad/s

The angular impulse-momentumTheorem states that the angular

Impulse on an object is equalTo the change in the object’s

Angular momentum.

τΔt = Lf - Li

The total momentum of all objectsInteracting with one another

Remains constant regardless of The nature of the forces

Between the objects.

m1v1i + m2v2i = m1v1f + m2v2f

The conservation of momentumCan be shown as a formula…

Momentum is conserved in Collisions and for objects

Pushing away from each other.

A 76 kg boater (Charlie), initially At rest in a stationary 45 kg boat, Steps out of the boat and onto the

Dock. If Ryan moves out of theBoat with a velocity of 2.5 m/s,

What is the final velocity Of his boat?

v2f = 4.2 m/s

An 85 kg fisherman jumps from aDock into a 135 kg rowboat at restOn the west side of the dock. If the

Velocity of the fisherman is 4.3 m/s to the west, what is the

Final velocity of the Fisherman and the boat?

1.66 m/s to the west

There are two kinds of collisions:

Those that bounce off of each otherAnd those that stick together

A perfectly inelastic collision is aCollision in which two objectsStick together and move with

A common velocity afterColliding.

m1v1i + m2v2i = (m1 +m2) vf

The formula for a perfectly Inelastic collision

An 1850 kg Cadillac stopped at a Light is struck from the rear byA Honda with a mass of 975 kg. The 2 cars become entangled.

If the Honda was moving at 22 m/s to the north before, what Is the velocity of the entangled

Mess after the collision?

vf = 7.59 m/s to the north

A grocery shopper tosses a 9 kg Bag of dog food into a stationary18 kg cart. The bag hits the cart

With a horizontal speed of 5.5 m/sToward the front of the cart. What is the final speed of the

Cart and bag?

1.8 m/s

The law of conservation of Angular momentum states thatIf no external torque acts on an

Object, then its angular momentumDoes not change.

L1 = L2

Iω = Iω