UNIT 5 ASSESSMENT

The space shuttle is located exactly half way between the earth and the moon. Which statement is true regarding the gravitational pull on the shuttle?

• The moon pulls more on the shuttle.

• The earth pulls more on the shuttle.

• Both are equal due to equal distances.

• Both are equal due to the mass of the shuttle.

An ebonite (very hard, black rubber) rod is rubbed with the four different substances below. Choose the one that is MOST likely to produce the largest static charge by friction.

• fur

• paper

• silk

• wax

Static charges can be applied to neutral objects by friction, induction or conduction. What do all of these methods utilize to create this charge?

• protons

• magnetic domains

• heat energy

• electrons

Mike wants to negatively charge a small rubber ball. Which of these methods would successfully charge the ball?

• heating the ball in boiling water

• running the ball over a strong magnet

• rubbing the ball back and forth on carpet

• dropping the ball from a tall building

Sal and Marie were experimenting with bar magnets in science class, picking up chains of paper clips. Where should they expect the magnetic force of the bar magnet to be the strongest and pick up the most paper clips?

• at both Poles

• at the South Pole

• at the North Pole

• in the center of the bar magnet

This graph shows the change in the force of gravity as distance increases. The graph will never reach zero, which suggests that

• gravity cannot cross space.

• the force of gravity does not change regardless of distance.

• every object exerts gravitational force on every other object.

• more distant objects exert a stronger gravitational force on other objects.

Which graph BEST represents the relationship between the electric current and the rate at which a magnet is turning inside an electric generator?

• 
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When a plastic ball is rubbed with fur, the plastic ball attracts a positively charged pith ball. When a glass rod is rubbed with fur, the glass rod repels the same pith ball. Based on these two observations, which of these will MOST LIKELY gain electrons more readily?

• fur

• glass

• plastic

• plastic and glass

During induction, a positively charged rod is brought near to but not touching the electroscope. The presence of the charged object above the plate of the electroscope induces charges to move down into the gold leaves, giving the electroscope an overall positive charge. The positive leaves repel. The same process occurs when the north poles of two magnets are brought close together: the two poles push away from each other. Both illustrate the principle that

• like charges or poles repel.

• induction produces magnetism.

• electricity induces magnetism.

• opposite charges or poles repel.

Lisa exposes an iron paper clip to a very strong magnet. She is now able to pick up other paper clips using her newly magnetized clip. What happens within the paper clip in order for it to become magnetized?

• The magnet randomizes the domains within the paper clip.

• Part of the strong magnet "rubs" off and joins to the paper clip.

• The strong magnet aligns the magnetic domains within the paper clip.

• The strong magnet creates an electric force filed around the paper clip.