AP Physics 2 Electrostatics & Momentum Quiz 3

A parallel–plate capacitor is charged by connection to a battery. If the battery is disconnected and the separation between the plates is increased, what will happen to the charge on the capacitor and the voltage across it?

• Both remain fixed.

• Both increase.

• Both decrease.

• The charge increases and the voltage decreases.

• The charge remains fixed and the voltage increases.

• 8.0 × 10^–24 N/C

• 9.1 × 10^–22 N/C

• 8.0 × 10^–6 N/C

• 2.0 × 10^–5 N/C

• 5.0 × 10⁴ N/C

Two conducting spheres of different radii, as shown above, each have charge –Q. Which of the following occurs when the two spheres are connected with a conducting wire?

• No charge flows.

• Negative charge flows from the larger sphere to the smaller sphere until the electric field at the surface of

  each sphere is the same.

• Negative charge flows from the larger sphere to the smaller sphere until the electric potential of each

  sphere is the same.

• Negative charge flows from the smaller sphere to the larger sphere until the electric field at the surface of

  each sphere is the same.

• Negative charge flows from the smaller sphere to the larger sphere until the electric potential of each

  sphere is the same.

Two parallel conducting plates are connected to a constant voltage source. The magnitude of the electric field between the plates is 2,000 N/C. If the voltage is doubled and the distance between the plates is reduced to 1/5 the original distance, the magnitude of the new electric field is

• 800 N/C

• 1,600 N/C

• 2,400 N/C

• 5,000 N/C

• 20,000 N/C

A 4 x 10^-6F capacitor is charged to a potential difference of 100 V. The electrical energy stored in the capacitor is

• 2 × 10^–10 J

• 2 × 10^–8J

• 2 × 10^–6J

• 2 × 10^–4J

• 2 × 10^–2 J

• 0

An object travels in the positive direction with a momentum of 5 kg⋅m/s . An applied force is exerted on the object, and a graph of the magnitude of the applied force as a function of time is shown. All frictional forces are considered to be negligible. Which of the following could represent the approximate momentum of the object after the force has been applied?

Select two answers.

• 0

• 3 kg m/s

• 5 kg m/s

• 7 kg m/s

• 10 kg m/s

Block X of mass M slides across a horizontal surface where friction is negligible. Block XX collides with block Y of mass 2M that is initially at rest, as shown in Figure 1. After the collision, both blocks slide together with a speed v_s , as shown in Figure 2.

What is the total kinetic energy of the two-block system before the collision?

Block X travels towards Block Y that is initially at rest, as shown in the figure, and eventually collides with Block Y. Which of the following diagrams represents the final velocities for Block X and Block Y after the collision if the collision is elastic?

• 
• 
• 
• 
• None of the collisions shown is an elastic collision.