Contents

1. Some comments
2. What will be on the test
3. Equation sheet
4. Test format
5. Examples of questions

1. Some comments

On problems, it is important to show how you reasoned from the information given in the problem to your final answer.  The correct final answer with units is only worth 2-3 points.  The remainder of the points are given for the quality of your solution.  You need to include the following to receive full credit:

All the information given in the problem with correct units (This may include a diagram)

A statement of what quantity you are trying to find.

State explicitly what physics principle you are using to solve the problem

Solve for the unknown quantity in symbols explicitly before numberic calculations

Then substitute numbers with units and calculate the numeric answer

Extra credit will be given for checks made to see if the answer is reasonable

Be prepared to make reasonable estimations and state your assumptions when solving problems. Be aware of significant digits in your answers. (Keep lots of digits until the final calculation, then round to the appropriate precision.)

Here are some really good tips on test taking from Dr. Richard Felder's website at North Carolina State University.

If you have ANY questions while taking the test, please be sure to ask the instructor. The purpose of the test is not to give you trick problems to catch you in an error. The purpose is to give you an opportunity to "show what you know" !  The test problems are based completely on the reading, the lectures, and the homework.  If you understand the main ideas and how to apply them, you'll do well.

Be sure to carefully review your notes, especially when we've done things that are not covered very well in the book. Looking over the individual class days linked to the calendar on the class website will also help refresh your memory. (Things to know from PHY 2048) For this test, you should be able to do the following things:

Chapter 22: Electric Charge

You will need to know the following equations and under what conditions they can be applied:

You should also know formulas for:

• area & circumference of a circle
• area & volume for a cube, a cylinder, & a sphere

You are expected to know the following conversions (rules of thumb):

• yard => meters
• miles => km
• inches => cm
• kg => lb
• quarts => liters

You should also know the following numbers to aid in visualization and estimation:

• your height and weight/mass in English and SI units
• The size of your hand
• The number of people who live in the Orlando Metropolitan Area
• The number of people in the US
• The distance from LA to New York
• The distance from Orlando to Miami
  

You are expected to derive specific equations you need from these equations listed above. You will also be given any constants and conversions you need. Unless told otherwise, you may use - 10 m/s^/s for the acceleration due to gravity.

4. Test Format:

Full period on Friday, March 14, 2003. A bonus of 5% will be awarded to any group (with active contract) whose average Test score is 75% is higher.
 

Part I
Group Problem using GOAL Protocol	25 points
Part II
Multiple Choice or short answer question, typically 4-5 parts             (no explanation required, but no partial credit either)	15-20 points
Estimation Problem	15 points
Short Essay (typically at least 1/2 page)	10 points
2 Problems based on Homework and Lecture – 15 points each	30-35 points
Total	100 points

5. Practice Tests

This link is to a test I gave when I taught this course as a SCALE-UP class at North Carolina State University. It intended only to show you the type of questions I ask on tests and to practice using what you have learned to prepare for Test 1. No solution is available yet, but you may discuss your solutions with me or ask questions about the problems in office hours, the review, or appointments made outside of class. However, I plan to post student solutions Wednesday night. If you wish to send me your solutions, I will award 5 points if your solution is chosen to be posted. Be aware that any topic discussed above in Section 2 or anything we have discussed in class, in the readings (other than recommended readings), or as homework is fair game for the test. Topics used in problems on the actual test may differ from topics covered in the practice test.

You will need adobe acrobat reader (v. 5 or better) to access the practice test.
 
 

6. Some Practice Questions

 
Multiple-Choice Practice Problem

To be added later

- This is a link to other multiple-choice problems that will help test your understanding of key ideas. The topics covered for this test can be found in Test 2. Note that some of these multiple-choice questions will exend beyond what we have learned so far in class and cover topics not included in Test 2.

Essay questions

1. Can your hand attract both a positive and a negatively object (one at a time)? Explain
2. Compare and contrast the force equation for universal gravitation with the Coulomb's force equation.
3. How can you induce a net charge on an object?

GOAL & Estimation Problems

1. You are helping to design a new electron microscope to investigate the structure of the HIV virus. A new device to position the electron beam
   consists of a charged circle of conductor. This circle is divided into two half circles separated by a thin insulator so that half of the circle can be charged positively and half can be charged negatively. The electron beam will go through the center of the circle. To complete the design your job is to calculate the electric field in the center of the circle as a function of the amount of positive charge on the half circle, the amount of
   negative charge on the half circle, and the radius of the circle.

2. A friend of yours in NASA administration has asked you about the feasibility of a new satellite launcher that will save rocket fuel. NASA's idea
   is basically an electric slingshot that consists of 4 small electrodes arranged at the corners of a horizontal square with sides of length d at a
   height h above the ground. The satellite is then placed on the ground aligned with the center of the square. A power supply will provide each of
   the four electrodes with a charge of +Q/4 and the satellite with a charge -Q. When the satellite is released from rest, it moves up and passes
   through the center of the square. At the instant it reaches the square's center, the power supply is turned off and the electrodes are grounded,
   giving them a zero electric charge. To test this idea, you decide to use energy considerations to calculate how big Q will have to be to supply the 100 megajoules needed to get a 100 kg satellite into a 100 km orbit. Assume that the satellite and electrodes are small enough to be treated as point charges, that the satellite starts from 15 meters below the square of electrodes, and that the sides of the square are each 5 meters long.
   

3. You have landed a summer job working with an Astrophysics group investigating the origin of high-energy particles in the galaxy. The group you are joining has just discovered a large spherical nebula with a radius 1.2 million km. The nebula consists of about 5e10 hydrogen nuclei
   (protons) which appear to be uniformly distributed in the shape of a sphere. At the center of this sphere of positive charge is a very small
   neutron star. Your group had detected electrons emerging from the nebula. A friend of yours has a theory that the electrons are coming from the
   neutron star. To test that theory, she asks you to calculate the minimum speed that an electron would need to start from the neutron star and just
   make it to outside the nebula. From the inside cover of your trusty physics text you find that the charge of a proton (and an electron) is 1.6e-19 C, the mass of the proton is 1.7e-27 kg, and the mass of the electron is 9.1e-31 kg.
   
   
4. You have a great summer job in a research laboratory with a group investigating the possibility of producing power from fusion. The device
   being designed confines a hot gas of positively charged ions, called plasma, in a very long cylinder with a radius of 2.0 cm. The charge density
   of the plasma in the cylinder is 6.0e-5 C/m3. Positively charged Tritium ions are to be injected into the plasma perpendicular to the axis of
   the cylinder in a direction toward the center of the cylinder. Your job is to determine the speed that a Tritium ion should have when it enters the
   plasma cylinder so that its velocity is zero when it reaches the axis of the cylinder. Tritium is an isotope of Hydrogen with one proton and two
   neutrons. You look up the charge of a proton and mass of the tritium in your trusty Physics text to be 1.6e-19 C and 5.0e-27 kg.

Homework and Lecture Problems

To be added later