Ocr P4 21st Century Quiz. Potential Energy, Kinetic Kinergy

1. What name is given to the energy of a moving object? E.g. A Car.

Heat

Gravitational Potential Energy

Electrical Potential Energy

Atomic Energy

Kinetic Energy

Kinetic energy is the energy possessed by a moving object. It is the energy that an object possesses due to its motion. In the given question, the example of a car is mentioned, which is a moving object, and it possesses kinetic energy. Heat, gravitational potential energy, electrical potential energy, and atomic energy are different forms of energy, but they are not specifically associated with the energy of a moving object. Therefore, the correct answer is kinetic energy.

Explanation

Kinetic energy is the energy possessed by a moving object. It is the energy that an object possesses due to its motion. In the given question, the example of a car is mentioned, which is a moving object, and it possesses kinetic energy. Heat, gravitational potential energy, electrical potential energy, and atomic energy are different forms of energy, but they are not specifically associated with the energy of a moving object. Therefore, the correct answer is kinetic energy.

2. A stone is dropped from the top of a cliff. How does the energy of the stone change as it falls from the top of the cliff to the ground below?

Kinetic Energy of the stone transforms to gravitational potential energy.

Kinetic energy of the stone is dissipated as heat.

Potential energy of the stone transforms to kinetic energy.

There is no change is potential energy.

There is no change in kinetic energy.

As the stone falls from the top of the cliff to the ground below, its potential energy decreases while its kinetic energy increases. This is because the stone is initially at a higher elevation, which gives it potential energy due to its position in the Earth's gravitational field. As it falls, this potential energy is converted into kinetic energy, which is the energy of motion. Therefore, the correct answer is that the potential energy of the stone transforms into kinetic energy.

Explanation

As the stone falls from the top of the cliff to the ground below, its potential energy decreases while its kinetic energy increases. This is because the stone is initially at a higher elevation, which gives it potential energy due to its position in the Earth's gravitational field. As it falls, this potential energy is converted into kinetic energy, which is the energy of motion. Therefore, the correct answer is that the potential energy of the stone transforms into kinetic energy.

3. What is the equation for the Work Done by a force on an object?

Gravitational Field Strength multipied by the mass of the object.

Force applied to an object multiplied by the distance the object moves. ( In the direction of the force).

The work done on an object does not depend on the force applied.

Kinetic energy of the object multiplied by the Gravitational Potential Energy of an object.

Force applied to an object divided by the distance the object moves ( In the direction of the force).

The equation for the work done by a force on an object is given by multiplying the force applied to the object by the distance the object moves in the direction of the force. This equation is derived from the definition of work, which is the transfer of energy that occurs when a force is applied to an object and it moves in the direction of the force. By multiplying the force and the distance, we can calculate the amount of work done on the object.

Explanation

The equation for the work done by a force on an object is given by multiplying the force applied to the object by the distance the object moves in the direction of the force. This equation is derived from the definition of work, which is the transfer of energy that occurs when a force is applied to an object and it moves in the direction of the force. By multiplying the force and the distance, we can calculate the amount of work done on the object.

4. An object is 5 metres high off the ground on earth. The object is then placed 5 metres high on the moon's surface. Assuming that the gravitational field strength on the moon is only half that of the earth, how does the gravitational potential energy of the object change on the moon?

It has doubled.

It has tripled.

There is no gravity in the whole of space, everything just floats around randomely.

It is halved

There is no change

The gravitational potential energy of an object is directly proportional to its height and the gravitational field strength. In this scenario, the object is placed at the same height on the moon as it was on Earth, but the gravitational field strength on the moon is only half that of Earth. Since the height remains the same and the field strength is halved, the gravitational potential energy of the object is halved as well.

Explanation

The gravitational potential energy of an object is directly proportional to its height and the gravitational field strength. In this scenario, the object is placed at the same height on the moon as it was on Earth, but the gravitational field strength on the moon is only half that of Earth. Since the height remains the same and the field strength is halved, the gravitational potential energy of the object is halved as well.

5. If the mass of an object is multipled by the Graviational Field Strength (g for earth), what does this give?

The objects height.

The objects width.

The objects weight.

The total energy of the object.

The density of the object.

When the mass of an object is multiplied by the gravitational field strength (g for Earth), it gives the object's weight. Weight is the force with which an object is pulled towards the center of the Earth due to gravity. It is directly proportional to the mass of the object and the gravitational field strength. Therefore, multiplying the mass by the gravitational field strength gives the weight of the object.

Explanation

When the mass of an object is multiplied by the gravitational field strength (g for Earth), it gives the object's weight. Weight is the force with which an object is pulled towards the center of the Earth due to gravity. It is directly proportional to the mass of the object and the gravitational field strength. Therefore, multiplying the mass by the gravitational field strength gives the weight of the object.

6. A man is walking at 1 metre per second (m/s). He has a mass of 100 kilogram (Kg). How much kinetic energy does he have?

He doesn't have any kinetic energy.

6 Mega (6,000,000) Electron Volts.

5 Joules.

50 Joules.

100 Joules.

The kinetic energy of an object can be calculated using the formula KE = 1/2 * mass * velocity^2. In this case, the man has a mass of 100 kg and is walking at a velocity of 1 m/s. Plugging these values into the formula, we get KE = 1/2 * 100 kg * (1 m/s)^2 = 50 Joules. Therefore, the man has 50 Joules of kinetic energy.

Explanation

The kinetic energy of an object can be calculated using the formula KE = 1/2 * mass * velocity^2. In this case, the man has a mass of 100 kg and is walking at a velocity of 1 m/s. Plugging these values into the formula, we get KE = 1/2 * 100 kg * (1 m/s)^2 = 50 Joules. Therefore, the man has 50 Joules of kinetic energy.

7. Your science teacher slides a book across the work bench or table. The book eventually stops after sliding. Is energy conserved in this situation?

All of the answers are true.

None of the answers can be true.

Yes. Energy is conserved. The Work done by the science teacher equals the change in energy of the book.

No. Friction opposes the motion of the book and the energy is dissipated as heat to the surroundings.

There is no such thing as conservation of energy.

In this situation, energy is not conserved because of the presence of friction. Friction opposes the motion of the book, causing it to eventually stop. As the book slides, the energy is converted into heat and dissipated to the surroundings. Therefore, the correct answer is "No. Friction opposes the motion of the book and the energy is dissipated as heat to the surroundings."

Explanation

In this situation, energy is not conserved because of the presence of friction. Friction opposes the motion of the book, causing it to eventually stop. As the book slides, the energy is converted into heat and dissipated to the surroundings. Therefore, the correct answer is "No. Friction opposes the motion of the book and the energy is dissipated as heat to the surroundings."

8. You are rolling a football along the ground. You get tired and you stop with the ball. What happened to the gravitational potential energy of the ball?

Increased.

Decreased.

Remained Zero.

None of the above.

Energy doesn't exist. Humans invented the idea to explain the unexplainable.

When the ball is rolling along the ground, it is in motion and has kinetic energy. Gravitational potential energy is the energy an object possesses due to its position above the ground. In this case, since the ball is on the ground, its height is zero and therefore its gravitational potential energy is also zero. When you stop with the ball, its position remains the same, so its gravitational potential energy remains zero.

Explanation

When the ball is rolling along the ground, it is in motion and has kinetic energy. Gravitational potential energy is the energy an object possesses due to its position above the ground. In this case, since the ball is on the ground, its height is zero and therefore its gravitational potential energy is also zero. When you stop with the ball, its position remains the same, so its gravitational potential energy remains zero.

9. If the kinetic energy of an object is doubled, how many times will its velocity increase by?

10 times

5 times

4 times

None at all

2 times

When the kinetic energy of an object is doubled, the velocity will increase by four times. This is because kinetic energy is directly proportional to the square of velocity. If the kinetic energy is doubled, it means that the square of velocity is also doubled. Taking the square root of the doubled value gives us a velocity that is increased by a factor of two. Therefore, the velocity will increase by four times when the kinetic energy is doubled.

Explanation

When the kinetic energy of an object is doubled, the velocity will increase by four times. This is because kinetic energy is directly proportional to the square of velocity. If the kinetic energy is doubled, it means that the square of velocity is also doubled. Taking the square root of the doubled value gives us a velocity that is increased by a factor of two. Therefore, the velocity will increase by four times when the kinetic energy is doubled.

10. An object moves a distance of 10 metres due to a force pushing it to the right. How much work is done on the object in the direction, which is perpendicular to the direction off travel?

20 Joules

10 Joules.

No work is done.

Same amount in all directions.

300 Joules.

When a force is applied perpendicular to the direction of travel, no work is done on the object. Work is defined as the product of force and displacement in the direction of the force. In this case, since the force is perpendicular to the direction of travel, the displacement in the direction of the force is zero. Therefore, the work done on the object is zero.

Explanation

When a force is applied perpendicular to the direction of travel, no work is done on the object. Work is defined as the product of force and displacement in the direction of the force. In this case, since the force is perpendicular to the direction of travel, the displacement in the direction of the force is zero. Therefore, the work done on the object is zero.