Do Now: What happens when you shoot one pool ball into another?

ObjectivesVocabulary State and give

examples of momentum and Newton’s 3rd Laws of Motion

Practice using these new concepts.

Newton's third law

momentum impulse law of

conservation of momentum

MOMENTUM

Momentum- amount of force needed to stop a moving object, it’s always conserved; never lost–

FORMULA p= mass x velocity

EX: a ball is 10 kg, and its velocity Is 5 m/s

so momentum = 10g x 5m/s = 50 kg m/s

What happens to the momentum?

Determine the momentum of a ...

60-kg halfback moving eastward at 9 m/s.

1000-kg car moving northward at 20 m/s.

40-kg freshman moving southward at 2 m/s.

Let’s Watch…

Bill Nye Momentum

Third Law

Action – Reaction Forces are always produced in pairs

with opposite directions & equal strengths

For every force there is an equal and opposite force

Let’s Watch! Newton's Thir

d Law Action Reaction

The truck is in motion. What is the force that causes it to stop?

The push of the stopped car.

The car is at rest. What is the force that causes it to move?

The push of the truck.

What about the ladder on top of the truck?

The ladder is in motion because the truck is in motion.

When the truck stops, the ladder stays in motion.

The truck is stopped by the force of the car, but the ladder is not.

What force stops the ladder?

Gravity.

The truck is in motion, the car is at rest. How do each of these vehicles accelerate?

The truck stops moving. The car starts moving.

Which one will be the hardest to accelerate?

The truck because it has the most mass.

Why does the car move [accelerate] when it is hit by the truck?

The heavy and moving truck has more force than the small, at rest car.

Why does the truck stop moving when it hits the car?

The force of the car pushing back on the truck, plus the force of friction between the massive truck and the road slow down, the stop the truck.

The truck hits the car. An action force stops the truck.

What is the equal and opposite reaction force?

The force that pushes the car forward.

Warner Brothers cartoon character Wile E. Coyote often finds himself falling off a cliff. Then a giant boulder usually lands on top of him after he hits the ground. If Wile E. Coyote and a boulder fall off a cliff at the same time, which do you think will hit the ground first?