One student rubs a balloon against his hair several times. Another student passes a comb through her hair several times. The students place the comb near the balloon and observe that the comb repels the balloon. Which is the most likely reason the comb is able to repel the balloon?

• The balloon has a positive charge and the comb is neutral.

• The balloon and the comb have the same electrical charge.

• The balloon has a negative charge and the comb is neutral.

• The balloon and the comb have opposite electrical charges.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

A student attaches a rope to the handle of a chest loaded with a few books, while the other end of the rope is tied to a spring scale. The student pulls the scale with just enough force to set the chest in motion and records the force applied on the spring scale. The student repeats the experiment with more books in the chest and records the data in a table.

What can be concluded from the data?

• As the mass of the chest increases, less force is required to pull it.

• As the mass of the chest increases, more force is required to pull it.

• The amount of frictional force increases as the mass of the chest decreases.

• The amount of frictional force decreases as the mass of the chest increases.

Tags

NGSS.MS-PS2-2

The diagram shows a firefighter operating a hose. The arrows show the forces acting on the hose.

Which statement describes the situation in the diagram?

• Since the firefighter is at rest, he does not move as he operates the hose.

• The hose has very little friction, making it slide toward the firefighter.

• The firefighter's mass decreases the force of the water escaping from the hose.

• The water escaping from the hose exerts an equal and opposite force on the hose.

Tags

NGSS.MS-PS2-1

A 100 kg box is initially at rest on a level surface. One 10 N force acts on the box, directed toward the right. A second 10 N force acts simultaneously on the box, directed toward the left, as shown.

How is the box affected by the two forces?

• The box will move because unbalanced forces are acting on it.

• The box will move because balanced forces are acting on it.

• The box will not move because unbalanced forces are acting on it.

• The box will not move because balanced forces are acting on it.

Tags

NGSS.MS-PS2-2

Four smooth blocks are being pushed along a smooth surface. The diagram shows the mass of the blocks and the force applied to each block.

What can be concluded about the motion of the blocks?

• Block 1 will move the farthest.

• Block 1 will move farther than Block 3.

• Blocks 2 and 3 will not move.

• Block 4 will move farther than Block 2.

Tags

NGSS.MS-PS2-2

Describe one way you can make an electromagnet stronger.

• Reduce the size of the iron core

• Decrease the current

• Decrease the energy source

• Increase the number of loops in the wire

Tags

NGSS.MS-PS2-3

The magnetic field is strongest at

• the north pole only

• in the middle

• at both poles

• at the south pole only

Tags

NGSS.MS-PS2-3

The buildup of charges on an object is called

• Current electricity

• Static electricity

• Electromagnetism

• Magnetic field

An iron nail wrapped with copper wire and attached to a battery makes —

• Permanent magnet

• Electromagnet

• Compass

• Metal magnet

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

A student inflates a balloon attached to a plastic straw. A string is threaded through the straw and tied to opposite ends of the room. When the air in the balloon is released, the balloon travels the length of the string. Which of Newton's laws explain this?

• The law of action-reaction

• Newton's law of magnetism

• The law of force and acceleration

• The law of gravity

Tags

NGSS.MS-PS2-1