Chapter 3Physics A First Course Forces and Motion

Forces and MotionConservation 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 LawKey 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

Newton's third law momentum impulse law of conservation

of momentum

Use Newton's third law to explain various situations.

Explain the relationship between Newton's third law and momentum conservation.

Solve recoil problems.

3B Investigation: Conservation of EnergyKey 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 energy

joule work potential

energy kinetic energy law of

conservation of energy

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.

Chapter 3.3 Objectives and Vocabulary collision

elastic collision inelastic

collision

Distinguish between elastic and inelastic collisions.

Use momentum conservation to solve collision problems.

Explain how momentum, impulse, force and time are related.