A person throws a ball up into the air. At which point in its path will the ball have the greatest potential energy?
The ball will have the greatest potential energy at the highest point of its path, which is the point where it stops moving upward for a split second and begins to fall back down. At this point, the ball has reached its maximum height and has the greatest potential energy because it has the greatest distance from the ground and can potentially do the most work when it falls back down.
A person throws a ball up into the air. At which point in its path will the ball have the greatest potential energy?
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1 point
When the ball is still rising
When the ball reaches its highest point
When the ball leaves the person’s hand
When the ball hits the ground
When the ball reaches its highest point.
This image of a roller coaster is designed to show important information about potential and kinetic energy. One of these pieces of information is incorrect. Which information is wrong, and why?
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1 point
The roller coaster would only have kinetic energy at the point labeled “gravitational potential energy and kinetic energy.”
The spot with the “maximum kinetic energy” should be on the lowest point of the roller coaster, at the far left side on the bottom.
The roller coaster would only have potential energy at the point labeled “gravitational potential energy and kinetic energy.”
The statement “The roller coaster would only have kinetic energy at the point labeled ‘gravitational potential energy and kinetic energy.’” is incorrect.
At any point on the roller coaster, it will have a combination of potential and kinetic energy. The point labeled “gravitational potential energy and kinetic energy” is where the roller coaster has the maximum potential energy converted to kinetic energy, but it still has some potential energy left. Therefore, the roller coaster has both potential and kinetic energy at this point.
Use the table of information from an investigation to answer the question.
Two students drop an object into sand from a height of 1.5 meters. They record the depth of the hole made in the sand by each student’s object. What is the most likely explanation for the results?
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1 point
Maddie’s object has a smaller width.
Naveed’s object has less mass.
Naveed’s object had greater kinetic energy.
Naveed's object had greater kinetic energy.
The depth of the hole in the sand depends on the amount of kinetic energy that the object has when it hits the sand. Kinetic energy is determined by the speed and mass of the object. Since both objects were dropped from the same height, they have the same initial potential energy. However, if Naveed's object had greater kinetic energy, it would have hit the sand with a greater speed and thus made a deeper hole. Therefore, the most likely explanation is that Naveed's object had greater kinetic energy.
A student wants to determine the effect of mass on kinetic energy. She will drop two balls of the same size into a pool of water. Which investigation method should the student use?
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1 point
She should drop two balls with different masses from different heights.
She should drop two balls with different masses from the same height.
She should drop two balls of the same mass from different heights.
She should drop two balls of the same size from different heights.
To determine the effect of mass on kinetic energy, the student should keep the height constant and vary the mass of the objects. This can be done by dropping two balls of the same size but different masses from the same height. However, dropping them into a pool of water might not be the best method as water resistance will affect the object's speed and may lead to inaccurate results. It would be better to use another type of surface that does not impede the motion of the balls.
Which statement explains how the charges on objects determine the electric force between them?
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1 point
Objects with positive charges attract each other, and objects with negative charges repel each other.
Objects with the same charge attract each other, and objects with opposite charges repel each other.
Objects with positive charges repel each other, and objects with negative charges attract each other.
Objects with the same charge repel each other, and objects with opposite charges attract each other.
Objects with the same charge repel each other, and objects with opposite charges attract each other.
According to Coulomb's law, the electric force between two objects depends on the magnitudes of their charges and the distance between them. Objects with like charges (positive or negative) repel each other because they have the same charge and therefore their electric fields push against each other, making it harder for them to get closer. Objects with opposite charges attract each other because the force of attraction between the opposite charges overcomes the repulsion caused by their electric fields.
Why is glass a good insulator?
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1 point
a) The atoms in glass hold on tightly to their negatively charged particles.
b) The atoms in glass hold on tightly to their positively charged particles.
c) The atoms in glass do not hold on tightly to their negatively charged particles.
a) The atoms in glass hold on tightly to their negatively charged particles.
Glass is a good insulator because the electrons in its atoms are tightly held and cannot move freely. This results in a high resistivity, which means that it resists the flow of electric current. Since the negatively charged electrons are restricted in their movement, it is difficult for charges to be transferred through the material. This makes glass a poor conductor of electricity and a good insulator.
Which statement describes a difference between insulators and conductors?
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1 point
a) Insulators have high resistance, while conductors have low resistance.
b) Insulators can transmit electric current, while conductors cannot.
c) Insulators have high conductivity, while conductors have low conductivity.
a) Insulators have high resistance, while conductors have low resistance.
Insulators and conductors both have different electrical properties. Insulators have a high resistance to the flow of electric current because they are poor conductors of electricity. On the other hand, conductors have low resistance because they allow electric current to flow easily through them. With respect to statement b), conductors do transmit electric current while insulators do not easily allow the flow of electric current through them. Statement c) is incorrect because insulators have low conductivity, while conductors have high conductivity.
Which energy transformation happens when a toaster is plugged in to an outlet in the wall and used to make toast?
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1 point
Electrical energy from the outlet is converted completely to heat energy for the toaster.
Electrical energy from the outlet is converted to heat and chemical energy in the toast.
Electrical energy from the outlet is converted to heat and light energy for the toaster.
Electrical energy from the outlet is converted to heat and light energy for the toaster.
When a toaster is plugged in, the electrical energy from the outlet is transformed into thermal energy (heat) and radiant energy (light) in the heating elements of the toaster. The heat generated by these elements is used to toast the bread, resulting in chemical changes in the bread due to the Maillard reaction. Therefore, the correct choice is that the electrical energy from the outlet is converted to heat and light energy for the toaster.