Physical Science Review test

Which phrase best describes a gravitational force?

• a force that spins objects

• a force that pulls objects toward each other

• a force that can make objects both attract and repel each other

• a force that acts only when two objects are in contact with each other

Answer explanation

Gravitational force is best described as a force that pulls objects toward each other, making this the correct choice among the options provided.

Tags

NGSS.MS-PS2-4

Some trains use a system known as maglev instead of wheels. In one version of maglev, magnets inside the track act on magnets inside the train, and when the train is at full speed it never touches the ground. The magnets never touch, but the force between them can be changed by adjusting the amount of current flowing through the train’s control system. What force do these maglev trains reduce by using magnets?

• elastic

• electrical

• friction

• tension

Answer explanation

Maglev trains reduce the force of friction by using magnets to levitate the train above the track, eliminating the need for wheels touching the ground.

Tags

NGSS.MS-PS2-5

Jimmie places a soccer ball on the ground and kicks it toward the goal. The ball moves along the ground toward the goal. Why does the ball move?

• The kick decreases the weight of the ball.

• The kick serves as a contact force on the ball.

• The kick decreases the force of gravity acting on the ball.

• The kick removes friction between the ball and the ground.

Answer explanation

The kick serves as a contact force on the ball.

Tags

NGSS.MS-PS2-2

The picture below shows Magnet 2 being pushed toward Magnet 1. Which of the following will most likely happen to Magnet 1 as Magnet 2 is moved closer?

• Magnet 1 will move under Magnet 2.

• Magnet 1 will move toward Magnet 2.

• Magnet 1 will move on top of Magnet 2.

• Magnet 1 will move away from Magnet 2.

Answer explanation

Magnet 1 will move away from Magnet 2 due to repelling magnetic forces between the two magnets.

Tags

NGSS.MS-PS2-5

Static electricity happens when electrons pass from one object to another, such as from your hair to a comb as you comb your hair. If you were to comb your hair and then hold the comb near your hair, strands of hair would move forward and appear to stick to the comb. How could the interaction between the hair and the comb be described?

• They repel each other because they have opposite charges.

• They repel each other because they have the same charges.

• They attract each other because they have opposite charges.

• They attract each other because they have the same charges.

Answer explanation

The hair and comb attract each other because they have opposite charges, causing the strands of hair to move forward and stick to the comb.

A person sitting in a rolling chair at rest throws a basketball forward. Since the person and the rolling chair have a greater mass than the basketball, how will the person and the rolling chair respond?

• They will have the same forward momentum as the basketball.

• They will move backward at a lower speed than the basketball moves forward.

• They will move backward at a higher speed than the basketball moves forward.

• They will travel the same distance as the basketball travels but in the opposite direction.

Answer explanation

The person and rolling chair will move backward at a lower speed than the basketball moves forward due to conservation of momentum.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

Four students push on a block of wood with the forces shown in the diagram below. Assume friction is negligible. If the block slides horizontally, what is the net force, in Newtons (N), acting on the block of wood?

• 7 N to the left

• 25 N to the left

• 11 N to the right

• 18 N to the right

Answer explanation

The net force is calculated by adding all the forces together. In this case, 25 N to the left and 7 N to the right cancel out, leaving a net force of 18 N to the right.

Tags

NGSS.MS-PS2-2

Which of the following is true about these objects?

• Both objects traveled the same distance.

• Both objects increased their speed as they traveled.

• Object 1 would have a steeper slope than Object 2 on a distance-time graph.

• Object 1 and Object 2 would have a horizontal line on a distance-time graph.

Answer explanation

Object 1 would have a steeper slope than Object 2 on a distance-time graph because it traveled the same distance in less time, indicating a higher speed.

Tags

NGSS.MS-PS3-1

The diagram below shows a closed circuit. What type of energy is the energy in the battery transformed into?

• light energy

• sound energy

• chemical energy

• electrical energy

Answer explanation

The energy in the battery is transformed into electrical energy, which powers the circuit and produces light energy.

Jackie used a portable electric drill to remove screws from a broken wooden table. He noticed that the screws holding the table together were warm to the touch after being removed from the wood. What explains this phenomenon?

• Mechanical energy from the drill was converted into thermal energy due to friction.

• Thermal energy from the drill was converted into mechanical energy due to inertia.

• Electrical energy from the drill was converted into chemical energy due to resistance.

• The process of removing the screw concentrated the thermal energy that was already present in the wood.

Answer explanation

Mechanical energy from the drill was converted into thermal energy due to friction.

Tags

NGSS.MS-PS3-5