# Ap physics c 2014 free response

• darksyesider
In summary: The motion always induces the magnetic field which will oppose the motion.Therefore...the motion always induces the magnetic field which will oppose the motion.
darksyesider
Please show your reasoning.

Uh first when it enters there is a CCW current so from F= ILxB, it accelerates.
Then while it is in the magnetic field there is no change so it is the same.
then when it leaves there is a CW current so it decelerates.
Then it stays the same at the end since no current.

By "accelerate" do you mean it moves faster? i.e. kinetic energy of the loop increases?

You are saying that as the loop enters the magnetic field, electrical energy is generated, so the kinetic energy of the loop also increases?

Try describing what happens in terms of conservation of energy.

darksyesider said:
Uh first when it enters there is a CCW current so from F= ILxB, it accelerates.
A few questions you need to answer to figure this out:
Which end of the loop is in the field as it is entering the field?
What is the direction of I in that end, if the current is CCW?
Finally, the direction of I×B is ___?

Then while it is in the magnetic field there is no change so it is the same.
I agree.

then when it leaves there is a CW current so it decelerates.
Try to answer the questions I listed above for this case.

Then it stays the same at the end since no current.
Yes.

Simon Bridge said:
Try describing what happens in terms of conservation of energy.
That is an alternate way to solve the problem, but since darksyesider has already worked out the direction (CCW or CW) of the current, I suggest continuing along that line of reasoning.

Actually there is an even simpler one just from the rule
... the motion always induces the magnetic field which will oppose the motion.
Therefore...

## 1. What is the format of the AP Physics C 2014 free response questions?

The 2014 AP Physics C free response section consists of two parts: a multiple-choice section and a free response section. The free response section includes three questions that assess knowledge and skills in both Mechanics and Electricity and Magnetism.

## 2. How long do I have to complete the AP Physics C 2014 free response section?

The free response section is 90 minutes long, and you should allocate about 30 minutes for each question. It is recommended that you plan your time carefully and not spend too much time on one question, as each question is weighted equally.

## 3. What types of problems can I expect in the AP Physics C 2014 free response section?

The free response questions in the 2014 AP Physics C exam cover a wide range of topics, including kinematics, dynamics, energy, momentum, circular motion, electrostatics, circuits, and magnetism. These questions will require you to apply your knowledge of physics concepts and problem-solving skills to real-world situations.

## 4. Can I use a calculator on the AP Physics C 2014 free response section?

Yes, you are allowed to use a calculator on the free response section of the 2014 AP Physics C exam. However, it is important to note that the use of a calculator is not necessary for all questions, and some questions may even prohibit the use of a calculator. It is important to read the instructions carefully and use your calculator strategically.

## 5. How is the AP Physics C 2014 free response section graded?

The free response section of the 2014 AP Physics C exam is graded by trained AP readers on a scale of 0-10 points for each question. The total score for the section is then converted to a scaled score of 0-5, with 5 being the highest possible score. The scoring rubrics for each question are released by the College Board after the exam.

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