Physics A First Course
Forces and Motion
Chapter 3
Forces and Motion
Conservation Laws
 3.1
Newton's Third Law and Momentum
 3.2
Energy and the Conservation of Energy
 3.3
Collisions
3A Investigation: Momentum and the Third Law
Key Question:
What makes moving objects
keep going at the same speed
in the same direction?
*Students read text section 3.1
AFTER Investigation 3A
3A Investigation Topics

Perform collision experiments.

Measure time intervals.

Calculate speed using measured time intervals.

Calculate momentum.

Describe activity using the law of conservation of
momentum.
Chapter 3.1 Objectives and Vocabulary

Use Newton's third law to
explain various situations.

Explain the relationship
between Newton's third law and
momentum conservation.

Solve recoil problems.

Newton's third law
 momentum
 impulse
 law of conservation
of momentum
3B Investigation: Conservation of Energy
Key Question:
What limits how much a
system may change?
*Students read text section 3.2
AFTER Investigation 3B
3B Investigation Topics

Measure time intervals.
 Calculate speed using measured time intervals.

Measure height.
 Graph speed vs. height of the car.
 Calculate potential energy.
 Use energy conservation to derive a formula for the
speed of the car in terms of energy.
Chapter 3.2 Objectives and Vocabulary
Describe work and energy.
 Calculate potential energy.
 Calculate kinetic energy.


Apply the law of conservation
of energy to explain the motion
of an object acted on by
gravity.
energy
 joule
 work
 potential
energy
 kinetic energy
 law of
conservation of
energy

Chapter 3.3 Objectives and Vocabulary

Distinguish between elastic and
inelastic collisions.

Use momentum conservation
to solve collision problems.

Explain how momentum,
impulse, force and time are
related.
collision
 elastic collision
 inelastic
collision
