Question

Electric motors create motion by using magnets and electromagnets. What can a person do to make an electric motor stronger? (1 point) Responses Add coils to the electromagnet and use larger magnets Add coils to the electromagnet and use larger magnets Add coils to the electromagnet and smaller magnets Add coils to the electromagnet and smaller magnets Remove coils from the electromagnet and use larger magnets Remove coils from the electromagnet and use larger magnets Remove coils from the electromagnet and use smaller magnets
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A girl is trying to make a simple electromagnet to help her pick up a piece of metal she dropped under a car. Which list of materials would she need to make an electromagnet?(1 point) Responses wooden rod for a core, copper wire, 12-volt battery wooden rod for a core, copper wire, 12-volt battery metal rod for a core, copper wire, 12-volt battery metal rod for a core, copper wire, 12-volt battery plastic rod for a core, copper wire, 12-volt battery plastic rod for a core, copper wire, 12-volt battery glass rod for a core, copper wire, 12-volt battery
Answer
Which statement is true about the variables that affect the force of gravity between two objects?(1 point) Responses Force of gravity is affected by the diameters of the objects and their distance from the Sun. Force of gravity is affected by the diameters of the objects and their distance from the Sun. Force of gravity is affected by the masses of the objects and the distance between their centers. Force of gravity is affected by the masses of the objects and the distance between their centers. Force of gravity is affected by the masses of the objects and the distance between their outermost edges. Force of gravity is affected by the masses of the objects and the distance between their outermost edges. Force of gravity is affected by the volume of the objects and their velocity relative to the Sun.
Answer
Below is a table that lists the different masses of planets and Steve’s mass. If Steve were standing on each planet, which is the correct order of the planets from the one that has the highest force of gravity to lowest force of gravity? (1 point) Responses Venus, Earth, Mars Venus, Earth, Mars Earth, Venus, Mars Earth, Venus, Mars Mars, Venus, Earth Mars, Venus, Earth Earth, Mars, Venus
Answer
Janice holds two negatively charged balloons near each other. What will happen with the balloons?(1 point) Responses The balloons will not move. The balloons will not move. The balloons will push away from each other. The balloons will push away from each other. The balloons will become neutral. The balloons will become neutral. The balloons will be attracted to each other.
Answer
If the mass of planet Earth doubled, how would the force of gravity between Earth and the Sun change?(1 point) Responses The force of gravity would decrease by half The force of gravity would decrease by half The force of gravity would increase four times The force of gravity would increase four times The force of gravity would double The force of gravity would double The force of gravity would not change
Answer
A student rubs a balloon made of rubber on his hair and notices that the balloon sticks to his hair afterwards. What happened to the electrical charges of both the student’s hair and the balloon?(1 point) Responses The balloon’s charge became neutral, and the hair’s charge became positive The balloon’s charge became neutral, and the hair’s charge became positive The balloon’s charge became negative, and the hair’s charge became positive The balloon’s charge became negative, and the hair’s charge became positive The balloon’s charge became positive, and the hair’s charge became positive The balloon’s charge became positive, and the hair’s charge became positive The balloon’s charge became negative, and the hair’s charge became negative
Answer
A student touches a rubber ball with a negatively charged plastic rod. How will the negative charges be distributed on the ball?(1 point) Responses Evenly distributed on the ball’s surface Evenly distributed on the ball’s surface On the ball’s surface where the rod touches the ball On the ball’s surface where the rod touches the ball Evenly distributed on the ball’s inside Evenly distributed on the ball’s inside On the bottom of the ball’s surface
Answer
A student investigates how charge is distributed in a conductor. She tapes two unopened cans of soda onto foam cups as shown below. The cans are touching each other. She places a negatively charged balloon near the can on the left as shown. In which direction do the negatively charged atoms inside the soda cans move? (1 point) Responses From the right to the left of the cans From the right to the left of the cans From the left to the right of the cans From the left to the right of the cans From the top to bottom of the cans From the top to bottom of the cans From the bottom to the top of the cans
Answer
A student combed his hair. Then he observed what happened to the water when he put the comb near the faucet as shown below. Why did the water’s path change? (1 point) Responses Due to induction, the charged comb attracted the neutrally charged water Due to induction, the charged comb attracted the neutrally charged water Due to conduction, the charged comb repelled the neutrally charged water Due to conduction, the charged comb repelled the neutrally charged water Due to induction, the charged comb repelled the neutrally charged water Due to induction, the charged comb repelled the neutrally charged water Due to conduction, the charged comb attracted the neutrally charged water
Answered by GPT-4 Turbo
To make an electric motor stronger, you can:

- Add more coils to the electromagnet
- Use larger and stronger magnets

The strength of an electromagnet increases with the number of turns in the coil, as well as the current passing through it. Using larger and stronger permanent magnets also contributes to the overall strength of the magnetic field interactions, thus enhancing the motor's torque and efficiency. Therefore, a combination of "add coils to the electromagnet and use larger magnets" would generally be the approach to make an electric motor stronger.
Answered by GPT-4 Turbo
To make an effective electromagnet, the girl would need:

- A metal rod for a core (preferably iron or another ferromagnetic material to concentrate and enhance the magnetic field)
- Copper wire (to wrap around the core and create the electromagnet when current flows through it)
- A power source such as a 12-volt battery (to provide the current that magnetizes the coil)

Thus, the correct list of materials would be: "metal rod for a core, copper wire, 12-volt battery."
Answered by GPT-4 Turbo
The force of gravity between two objects is affected by:

- The masses of the objects
- The distance between their centers

These relationships are described by Newton's Law of Universal Gravitation, which states that the gravitational force between two masses is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

Therefore, the correct statement is: "Force of gravity is affected by the masses of the objects and the distance between their centers."
Answered by GPT-4 Turbo
To answer this question, we would need to consider not only the masses of the planets but also their radii, as gravity on the surface of a planet is determined by both the mass of the planet and the distance from the center of the planet to the surface (which is essentially the planet's radius).

Without specific numerical values for planetary masses and radii provided in your question, we can still rely on general knowledge:

- Earth has a greater mass than Venus, which in turn has a greater mass than Mars.
- Venus has a slightly smaller radius than Earth, and Mars has a significantly smaller radius than both Earth and Venus.

Because the force experienced by Steve (gravity) on the surface of a planet depends on the mass of the planet and how far Steve is from the planet's center (radius), the general knowledge suggests that the gravitational force would be strongest on Earth due to its greater mass and size, followed by Venus with a slightly weaker force because of its slightly smaller size and mass, and weakest on Mars due to its much smaller size and mass compared to Earth and Venus.

Therefore, the correct order from the planet with the highest force of gravity to the lowest force of gravity, assuming Steve's mass remains constant, would be:

- Earth
- Venus
- Mars

So the response "Earth, Venus, Mars" would be the correct order, based on expected gravitational forces on Steve if he were standing on each planet.
Answered by GPT-4 Turbo
Like charges repel each other. Given that both balloons are negatively charged, they will repel each other when brought near one another.

Therefore, the correct response is: "The balloons will push away from each other."
Answered by GPT-4 Turbo
According to Newton's Law of Universal Gravitation, the gravitational force (F) between two objects is directly proportional to the product of their masses (m1 and m2) and inversely proportional to the square of the distance (r) between their centers:

\[ F = G \frac{{m1 \cdot m2}}{{r^2}} \]

where \( G \) is the gravitational constant.

If the mass of planet Earth doubled, keeping the distance between Earth and the Sun constant, then according to the formula, the gravitational force between Earth and the Sun would also double.

Therefore, the correct response is: "The force of gravity would double."
Answered by GPT-4 Turbo
When a balloon is rubbed on hair, electrons are transferred from the hair to the balloon. This transfer of electrons causes the balloon to become negatively charged (since it gains electrons), and the hair becomes positively charged (since it loses electrons).

Therefore, the correct response is: "The balloon’s charge became negative, and the hair’s charge became positive."
Answered by GPT-4 Turbo
When a negatively charged rod is brought into contact with a rubber ball, some of the excess electrons on the rod will transfer to the rubber ball. If the ball is a conductor and the charges are free to move, the negative charges will repel each other and spread out over the surface of the ball to be as far away from each other as possible. However, if the rubber ball is an insulator, the charges may not move as freely.

In the case of a conductive ball:
The response would be "Evenly distributed on the ball’s surface." The negative charges would distribute across the surface of the ball to minimize repulsion between them, assuming the ball is placed in an isolated system where it isn't influenced by other external charges.

In the case of an insulating ball:
The negative charge may remain more localized around the area where the rod touches the ball because electrons in insulators do not move freely throughout the material.

If the question implies the ball is conductive, or if it doesn't specify the material's conductive properties, the widely accepted response would be "Evenly distributed on the ball’s surface," assuming the ball can conduct charges.
Answered by GPT-4 Turbo
In the scenario described, the cans are conductors as they are made of metal, which allows for the free flow of electric charge. When a negatively charged balloon is placed near the can on the left, negative charges (electrons) in the cans will be repelled by the negative charge of the balloon.

Since like charges repel, the electrons in the cans will move away from the balloon. Since the cans are touching, the charges can move through both cans. Therefore, the electrons will move from the can on the left (closer to the negatively charged balloon) to the can on the right.

The correct response is: "From the left to the right of the cans."
Answered by GPT-4 Turbo
When the student combed his hair, the comb likely became negatively charged by picking up extra electrons from the hair. When the charged comb was brought near the stream of water from the faucet, the water's path changed because of electrostatic attraction. This is due to a process known as electric polarization or induction.

Water molecules are polar, which means they have a slight positive charge on one side (where the hydrogen atoms are) and a slight negative charge on the other side (where the oxygen atom is). When the negatively charged comb is brought close to the water, the positive charges in the water molecules are attracted toward the comb, while the negative charges are repelled. This causes the water molecules to reorient so that their positive sides face the comb and the negative sides face away. This reorientation results in an overall movement of the water towards the comb because the attraction between the comb's negative charge and the positive charge in the water molecules is stronger than the repulsion between the comb's negative charge and the negative side of the water molecules.

Therefore, the correct response is: "Due to induction, the charged comb attracted the neutrally charged water."