Unit 3: Electricity & Magnetism Post Test

Select all the correct answers. According to Newton’s law of universal gravitation, which statements are true?

• As we move to higher altitudes, the force of gravity on us decreases.

• As we move to higher altitudes, the force of gravity on us increases.

• As we gain mass, the force of gravity on us decreases.

• As we gain mass, the force of gravity on us increases.

• As we move faster, the force of gravity on us increases.

Answer explanation

As we move to higher altitudes, gravity decreases due to the increased distance from the Earth's center. Conversely, as we gain mass, the gravitational force we exert increases, aligning with Newton's law.

Tags

NGSS.HS-PS2-4

Select all the correct answers. An unmanned spacecraft leaves for Venus. Which statements about the spacecraft’s journey are true?

• The weight of the spacecraft keeps changing.

• The mass of the spacecraft keeps changing.

• The weight of the spacecraft remains the same.

• The mass of the spacecraft remains the same.

• The gravitational pull on the spacecraft remains the same.

Answer explanation

The weight of the spacecraft changes due to varying gravitational forces as it travels, while its mass remains constant since it does not lose or gain material.

Tags

NGSS.HS-PS2-4

Select all the correct answers. Antonio is holding a 1-pound bag of apples in his left hand and a 2-pound bag of apples in his right hand. Which sentences about this situation are true?

• The force caused by gravity is the same on each bag.

• Antonio is applying a 1-pound force to hold the 1-pound bag.

• Antonio must apply a greater force to hold the 1-pound bag than the 2-pound bag.

• The acceleration due to gravity is greater on the 2-pound bag.

• The mass of the bag in his left hand is less than the mass of the bag in his right hand.

Answer explanation

Antonio applies a 1-pound force to hold the 1-pound bag, matching its weight. He must apply a greater force to hold the 2-pound bag, as it weighs more. The other statements about gravity and mass comparisons are incorrect.

Tags

NGSS.HS-PS2-1

Select the correct location on the image. The image shows positions of the Earth and the Moon. In which region would an astronaut feel the lightest?

Answer explanation

An astronaut would feel lightest at the point between the Earth and the Moon, where gravitational forces from both bodies balance out, creating a microgravity environment.

Tags

NGSS.HS-PS2-4

NGSS.HS-ESS1-4

Drag each label to the correct location on the chart. Based on Newton’s law of universal gravitation, complete the following table.

Groups:

(a) Gravity Increases When

,

(b) Gravity Decreases When

• Mass Increases

• Mass Decreases

• Distance Decreases

• Distance Increases

Answer explanation

According to Newton's law of universal gravitation, as mass increases, the gravitational force also increases. Therefore, the correct label to place is 'mass increases', indicating a direct relationship with gravity.

Tags

NGSS.HS-PS2-4

Select all the correct answers. A silk cloth gains electrons when rubbed over a glass rod. A different glass rod gains electrons when rubbed with rabbit fur. What will happen if the two charged glass rods approach one another and why?

• The rods will repel each other because they have unlike charges.

• There will be no reaction between the rods.

• The rods will attract each other because they are both positively charged.

• The rods will attract each other because they have unlike charges.

• The rods will repel each other because they have like charges.

Answer explanation

The silk cloth gains electrons, making one glass rod negatively charged, while the other rod gains electrons from rabbit fur, becoming positively charged. Unlike charges attract, so the rods will attract each other.

Tags

NGSS.HS-PS2-4

Select all the correct answers. When people use plastic combs on their hair, the combs become negatively charged. Which statements about this situation are true?

• The comb loses electrons.

• The comb gains electrons.

• The hair loses electrons.

• The hair gains protons.

• The hair loses protons.

Answer explanation

The comb gains electrons from the hair, making it negatively charged. Consequently, the hair loses electrons, resulting in a positive charge. The statements about the comb gaining electrons and the hair losing electrons are true.

Tags

NGSS.HS-PS3-5

Select the correct answer from each drop-down menu. Two magnets are placed as shown in the image.

• The force of repulsion between the poles B and C is minimum. And the force of attraction between the poles A and D is maximum.

• The force of attraction between the poles B and C is maximum. And the force of repulsion between the poles A and D is minimum.

• The force of repulsion between the poles A and B is maximum. And the force of attraction between the poles C and D is minimum.

• The force of attraction between the poles A and C is minimum. And the force of repulsion between the poles B and D is maximum.

Answer explanation

The correct choice states that the force of repulsion between poles B and C is minimum, indicating they are like poles, while the force of attraction between poles A and D is maximum, indicating they are opposite poles.

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

Which of the following objects are magnetic?

Groups:

(a) Magnetic

,

(b) Nonmagnetic

• Steel Tank

• Glass Marbles

• Silver Medal

• Iron Ball

• Wooden Table

• Nickel Hinge

Answer explanation

The iron nail is magnetic because it is made of iron, a ferromagnetic material. In contrast, the plastic spoon, copper wire, and rubber band are not magnetic as they do not possess magnetic properties.

Tags

NGSS.MS-PS2-3

Objects A and B are brought close to each other. Object A will soon become positively charged. Identify the charge that must transfer for this situation to occur.

Answer explanation

For object A to become positively charged, it must lose electrons. Therefore, electrons must transfer from object A to object B, resulting in A having a positive charge.

Tags

NGSS.HS-PS2-4

NGSS.HS-PS2-5

NGSS.HS-PS3-5