Download AP Physics Assignment Sheet - MECHANICS

Physics Assignment Sheet – CONSERVATION LAWS
Energy and Momentum
TEXT: COLLEGE Physics, 7th Ed., Serway and Faughn, Chapters 5, 6
Objectives for Concept Learning:
After studying this unit, you should be able to do the following:
1. Define work based on the force that is doing the work.
2. Identify the sign of work depending on the direction of the force relative to displacement.
3. Understand how work changes the energy of a system.
4. Visualize the meaning of kinetic energy and know how to calculate it.
5. Distinguish: the energy value at an instant versus the change in energy.
6. Understand how potential energy relates to work: W c = -∆PE
7. Visualize the difference between a conservative and a nonconservative force.
8. Be able to calculate both gravitational and elastic potential energy.
9. Understand that energy is relative: PE must have a reference level.
10. Distinguish between Hooke's Law for ideal springs and the elastic potential energy
equation for ideal springs.
11. Apply conservation of mechanical energy for many different types of problems.
12. Understand power as a rate of energy delivery.
The following are not required until Chapter 6 is complete:
13. Visualize the meaning of momentum.
14. Understand momentum as a vector quantity (energy is a scalar).
15. Define impulse; understand how impulse changes momentum.
16. Apply momentum conservation in a collision or explosion application.
17. Be able to tell in a problem where you may apply conservation of energy and where you
may apply conservation of momentum.
18. Know the difference between elastic and inelastic collisions.
19. Know how to calculate the loss of mechanical energy during a collision.
20. Predict the motion that results from a 2-dimensional, glancing collision.
The Table on the next page just shows where the textbook reinforces each major concept with
practice problems. The odd ones let you check yourself with answers in the back of the book.
The first test on Conservation Laws will be December 7 and will cover the Chapter 5 sections. In
the objectives above, that will not include momentum and impulse but will include power.
There will be another test later that will cover both Chapters 5 and 6. The two topics are
inseparable. The problems that combine both topics are labeled on the next page with the
instruction to Become Invincible Now. #56 from Chapter 6 happens to be my favorite, and its
hints will be on Edlio.
Topic
1
Topic
Sections 5.1, 5.2
Work Energy Theorem
PROBLEMS/QUESTIONS
Ch. 5: 1-17 odd
2
Section 5.3, 5.4, 5.7
Potential Energy
Ch. 5: 19-25 odd
3
5.4’s examples in text and
section 5.5
Applying Conservation
of TME
Ch. 5: 27-47 odd
63, 69, 71, others of your
choosing
4
5
6
7
5.6 - Power
Section 6.1 and 6.2
Impulse and momentum
Notice the similarity to
Assn. 1: Work is to
impulse as KE is to
momentum
Section 6.3 - read critically
and conceptually. Do not
memorize the formulas of
this section. Instead, apply
the strategy in green on
page 173
Make rules to recognize
when a situation calls for
Conservation of Energy
and when a situation calls
for Conservation of
Momentum.
Only people who do this
have successfully
completed the unit.
LABS/HANDOUTS
Work-Energy Theorem:
 Find k on my taped
air track
Vertical Stable Equilibrium
with PEelas and PEgrav, a
bungee jumper
Problem 69 is Broken Down
in a set of notes
This is the heart of Chapter
5. Mastering Chapter 5
means full self-sufficiency
in this area right here.
Ch. 5: 49, 51, 53
Ch. 6: 1 thru 17 odd
Worksheet 6.1 and 6.2
My Red Car/Blue Car model
and its associated packet
Chap 7: 19 thru 45 odd
Review Problems –
Become invincible now
Ch. 6: 47, 48, 52, 55, 56,
58, 74, 67, 72
Experiment: Ballistic
Pendulum
Energy Stored in a Crossbow
Interactive Physics: Collision
Energy Before and After
Two months from now, the
successful people will still
know to use these
conservation laws when the
situation calls for it. They will
recognize without clues or
hints which situation calls for
conservation of momentum
and which calls for
conservation of energy.
Calendar:
12/3: Practice on Topics 1, 2, and 3 above
12/3: Formulating Elastic PE on a spreadsheet
12/7: Chapter 5 Test
You’ll be tested on Chapter 5 again sometime after 12/6, and it will be mixed in with
Chapter 6. Deciding when to apply Conservation of Energy versus when to apply
Conservation of Momentum versus when to apply FBD/VI Method versus when to set up
Basic Kinematics. When such decisions are makeable by you, you’re working
independently as a physicist.