AP 2: Electrostatics and AP 1 Quiz #1

Small, negatively charged plastic beads are launched horizontally beneath a flat, positively charged plate, as shown in the figure. The beads follow various paths in the region beneath the plate. A student is asked to explain a calculation of the magnitude of the external force that must be exerted on the plate to keep it stationary. Which of the following lists the forces in the explanation that must be added to determine the external force?

• The gravitational force that Earth exerts on the plate only

• The force the plate exerts on the beads and the force the beads exert on the plate

• The gravitational force that Earth exerts on the plate and the force the plate exerts on the beads

• The gravitational force that Earth exerts on the plate and the force the beads exert on the plate

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

NGSS.HS-PS3-5

The figure shows an electron e that is at the center of a square configuration of fixed particles. Each particle has a charge of magnitude q and sign as shown. Which of the following is a correct force diagram for the electron?

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Tags

NGSS.HS-PS2-4

The figures show situation 1 and 2. In situation 1, a positively charged 0.10kg insulating sphere is suspended at rest 0.10 m above a large positively charged metal plate. In situation 2, a positively charged 0.20 kg insulating sphere is located 0.20 m above the positively charged metal plate and is in motion. The magnitudes of the charges on the spheres are the same.

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Tags

NGSS.HS-PS2-4

Negatively charged object A is attached to an uncharged wall made of insulating material. Negatively charged object B is connected to the wall by an insulating string. When object B comes to rest, it is displaced an angle θ from the wall, as shown. A free-body diagram for object B is also shown, with the magnitudes of the forces labeled. Which of the following is correct for the forces on object B?

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Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

Three objects are held along a line, as shown in the figure. Particle P with charge −q and mass m is a distance d from sphere AA with charge −q. Sphere B with charge +2q is a distance d on the other side of sphere A. The electric forces exerted on each of the objects is also shown, and gravitational forces are negligible. Particle P is then released. What is the magnitude of its acceleration immediately after release?

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Tags

NGSS.HS-PS2-1

The figure shows three point charges with charges +q+, −3q , and −5q located at the vertices of an equilateral triangle with side length a . Which of the following correctly characterizes the magnitude Fnet of the net electric force exerted on the positive charge?

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Tags

NGSS.HS-PS2-4

Three identical conducting spheres are arranged on insulating stands and equally spaced, as shown. Sphere 1 initially has a net charge of Q0 , while spheres 2 and 3 are initially uncharged. Sphere 1 is touched briefly to sphere 2 and moved away; then sphere 2 is touched briefly to sphere 3 and moved back to the configuration shown. After the processes, in which direction, if any, is the net electric force exerted on sphere 2?

• In no direction, because the net force is zero

• To the left

• To the right

• It cannot be determined without knowing the charge distribution on the surface of the spheres.

Tags

NGSS.HS-PS2-4

Two particles, with charges of +1 μC and −1 μC, are placed at the opposite corners of a cube with edges of length 0.01 m, as shown in the figure. The magnitude of the electric force on a third particle with charge +1 μC placed on the corner of the cube labeled P is most nearly

• 90 N

• 100 N

• 127 N

• 135 N

Tags

NGSS.HS-PS2-4

A rod initially at rest as shown in the figure rotates freely around a pivot such that frictional forces are considered to be negligible. The rod is divided equally into four sections, with the length of each segment equal to 2.0m. A downward force F1=100N is applied in the position and direction shown. A student must apply a force F2 to the rod so that the rod remains in equilibrium. To satisfy the condition, what magnitude of force can be exerted on the rod and at what distance away can F2 be applied? Select two answers.

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Tags

NGSS.HS-PS2-1

A block of mass 0.5kg on a horizontal surface is attached to a horizontal spring of negligible mass and spring constant 50N/m. The other end of the spring is attached to a wall, and there is negligible friction between the block and the horizontal surface. When the spring is unstretched, the block is located at x=0m. The block is then pulled to x=0.5m and released from rest so that the block-spring system oscillates between x = −0.5m and x = 0.5m, as shown in the figure. Which of the following claims is correct about the block’s period of oscillation?

• The period would increase if the block were released from rest at x = 0.8m

• The period would increase if the block had a mass of 1.2 kg

• The period would increase if the spring had a spring constant of 75N/m.

• The period would increase if the block-spring system was oriented vertically so that the block-spring system oscillates between y = −0.5m and y = 0.5m, the mass of the block is 0.5 kg, and the spring constant is 50 N/m