Physics 131

Homework

Part of the weekly homework assignment is in WebAssign, and part will be done on paper and handed in in class.

NOTE: The homework will be scanned to guard against lost papers. As a result it is very important that you DO NOT STAPLE OR ATTACH YOUR PAGES IN ANY WAY. If you do so, the scanner may destroy them. Also, if you have torn your pages out of a spiral bound notebook, please remove the performations.

The WebAssign homework is due on Friday at 5 PM and the paper homework is due at the beginning of the last lecture of the week.

Please note that WebAssign has some quirky rules for what can be entered where. If it is not accepting your answer check out: Answers that cannot be understood. Please follow the instructions for the problems that are given in the WebAssign environment. The links below are to public forms of the problem and may not include specialized WebAssign instructions.

You will be asked to do 3-5 challenging problems including estimations, explanations, essay questions, worked out problems, and even some challenging multiple choice questions. You are encouraged to work on these with friends. The course center is a good space to work together and get feedback from a TA or Professor. CLICK FOR THE COURSE CENTER SCHEDULE.

You have to write up your solutions independently. Be careful: If two or more submitted answers are essentially identical, neither will receive credit. If your solution is essentially identical to one found on the web, you will receive no credit and all your previous answers will be searched to see if they are also copied. Credit for those found to be copied will be removed.

Some of the WebAssign problems (mostly multiple-choice) will be computer-graded, some will be graded for correctness by a human, and some won't be graded (and you'll just get points for completion). However, we won't tell you ahead of time which problems will be graded, so you'll have to do your best on all of them! For the problems that are only graded for completion, make sure you look at the solution afterwards (posted on ELMS); don't let your perfect score on that problem (based on completion) fool you into thinking you did it correctly. (Maybe you did do it correctly, but it's good to confirm that.)

So you got your homework back and you see (especially on ones you lost points) some funny letters, like some kind of code. Here's what those letters mean. The burden of figuring out where you went wrong is on your shoulders, but if the code isn't helping you, bring your confusion to the Course Center.

Previous semesters of students have cried out for practice problems, so we are starting a page for that here. While we don't think that mastering these will prove anything about your knowledge of physics, or your ability to "think like a physicist," we do acknowledge that these can build your math skills for use on real problems. (Do not expect that exam or quiz questions will look like these!) We will not grade these, but you can bring up questions about these practice problems in Course Center hours or on the discussion board on ELMS.

Due date
(Fri)
Online HW
(due at 5 PM)
Paper Hand in HW
(due Beginning of last Lecture of the week)


HW 01

(9/9)

1. A homeopathic drug
2. Growing fingernails
3. Finding a mistake using dimensional analysis
4. Dimensions of pressure
Scaling up


HW 02

(9/16)

1. Moving a vesicle
2. A remote controlled car
3.A The tortoise and the hare (Q)
   B The tortoise and the hare (S)
4. Finding a small tumor
5. Acceleration at the top
Drawing consistent graphs


HW 03

(9/23)

1. How fast do you need to go?
2. Testing the motion detector
3. Pushing a block on a block - qualitative
4. Molly on the skateboard
5. Slime mold spores
The farmer and the donkey


HW 04

(9/30)

1. Blood test velocity
2. Pushing a block on a block - symbolic
3. Equations of counting
4. Stretching two springs
5. Kicking a car
Nathan's train


HW 05

(10/14)

1. Pushing a block on a block - quantitative
2. Propelling a paramecium 2 - estimations
3. Rolling up and down
4. Three-charge problems
Counting charges


HW 06

(10/21)

1. Vector subtraction practice
2. But it's just a leetle bit different
3. Electric forces on charges
4. Taking Cyrano to the moon
5. Molecular collisions 2

Water-coat forces


HW 07

(10/28)

1. Momentum conservation in subsystems
2. Colliding carts
3. Closing the door
4. Random or not, here I come
5. Diffusion in time and space
Oil-water electric forces

HW 08

(11/4)

1. Molarity and number density
2. Floating fish
3. The meteor and the dolphin
4. Feeling dizzy
5. Kinetic theory and pressure
PhET under pressure

HW 09

(11/18)

1. How many ions?
2. Blood flow in a constricted artery
3. Springy cart on a track
4. Sliding down a ramp
5. Fan carts P&E
What if the Greenland ice sheet melts?

HW 10

(12/2)

1. A superelastic collision
2. Potential energy of charges
3. Bound states
4. Going to a deeper well
5. Rolling down the electric hill
Energy in photosynthesis - a toy model

HW 11

(12/9)

1. Exothermic reactions: Macroscopic and nanoscopic
2. The penny and the jelly donut
3. Heating water in a copper pot
4. Cells as Laplace bubbles
5. A biologist, a physicist, and a chemist...
Potential energies for charge clusters
University of Maryland