Electricity and Magnetism #3 Free Response Question Solutions - AP Physics C 1998 Released Exam

The video tutorial covers solutions to a problem from the AP Physics C 1998 exam, focusing on electricity and magnetism. It explains the setup of a three-dimensional circuit with a bar moving down inclined rails in a magnetic field. The tutorial walks through calculating the current at terminal velocity, determining the terminal speed, calculating power dissipation, expressing speed as a function of time, and analyzing the effect of adding a resistor. The video emphasizes understanding the physics concepts and provides strategies for tackling algebra-heavy problems.

What is the significance of the angle Theta in the problem setup?

• It is the angle of the magnetic field.

• It is the angle of the incline of the rails.

• It is the angle of the resistor.

• It is the angle between the current and the magnetic field.

Which rule is used to determine the direction of the current in the bar?

• Ampere's rule

• Left-hand rule

• Right-hand rule

• Fleming's rule

What is the relationship between the magnetic force and the force of gravity when the bar reaches terminal velocity?

• Magnetic force is unrelated to the force of gravity.

• Magnetic force is less than the force of gravity.

• Magnetic force is greater than the force of gravity.

• Magnetic force is equal to the force of gravity.

What is motional EMF?

• The potential difference due to a stationary magnetic field.

• The potential difference due to a moving magnetic field.

• The potential difference across a moving bar in a magnetic field.

• The potential difference across a stationary bar.

How is the terminal speed of the bar calculated?

• By using the potential difference and the magnetic field.

• By using the current and the length of the bar.

• By using the mass and the angle of the incline.

• By using the resistance and the magnetic field.

Which formula is used to calculate the power dissipated in the circuit?

• Power = Voltage x Current

• Power = Current x Resistance

• Power = Current^2 x Resistance

• Power = Voltage^2 / Resistance

What is the initial velocity of the bar when it is released?

• Equal to the terminal velocity

• Zero

• Greater than zero

• Less than zero

How does the speed of the bar change over time according to Part D?

• It increases linearly.

• It decreases exponentially.

• It remains constant.

• It approaches a terminal speed exponentially.

What happens to the equivalent resistance when a second identical resistor is added in parallel?

• It decreases.

• It becomes zero.

• It remains the same.

• It increases.

How does adding a second resistor in parallel affect the final velocity of the bar?

• The final velocity increases.

• The final velocity becomes zero.

• The final velocity decreases.

• The final velocity remains the same.