Work Power Energy IGCSE
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Which of the following is not a unit for power?
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Joule – second
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Watt
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Newton-meter per second
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Horsepower
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This quiz includes the topics on Work, Energy and Power. The quiz is consisting of 15 multiple-choice items, which are all conceptual. Time limit for the quiz is 15 minutes. Good luck.
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- 2.
Car A has a mass of 1000 kg and a speed of 60 km/h, and car B has a mass of 2000 kg and a speed of 30 km/h. The kinetic energy of car A is _____.
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Half that of car B
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Equal that of car B
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Twice that of car B
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Four times that of car B
Correct Answer
A. Twice that of car BExplanation
The kinetic energy of an object is calculated using the formula KE = 1/2 * mass * velocity^2. Car A has a mass of 1000 kg and a speed of 60 km/h, while car B has a mass of 2000 kg and a speed of 30 km/h. Plugging in these values into the formula, we find that the kinetic energy of car A is twice that of car B.Rate this question:
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- 3.
If an object has kinetic energy, then it also must have _____.
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Speed
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Impulse
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Acceleration
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Force
Correct Answer
A. SpeedExplanation
If an object has kinetic energy, it means that it is in motion. Speed is a measure of how fast an object is moving, so if an object has kinetic energy, it must also have speed. Impulse, acceleration, and force are not necessarily required for an object to have kinetic energy.Rate this question:
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- 4.
A feather and a coin are dropped in the air. Each falls with equal _____.
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Momenta
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Kinetic energies
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Potential energy
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None of the above
Correct Answer
A. None of the aboveExplanation
When a feather and a coin are dropped in the air, they do not fall with equal momenta, kinetic energies, or potential energy. The feather experiences more air resistance due to its large surface area and low mass, causing it to fall slower than the coin. Therefore, the correct answer is "none of the above".Rate this question:
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- 5.
When a bullet is fired from a rifle, the force on the rifle is equal to the force on the bullet. However, the energy of the bullet is greater than the energy of the recoiling rifle because the _______.
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Force on the bullet acts for a longer distance
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Bullet's momentum is greater than that of the rifle
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Force on the bullet acts for a longer time
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The impulse of the bullet is more
Correct Answer
A. Force on the bullet acts for a longer distanceExplanation
The force on the bullet acts for a longer distance, which means that the bullet is accelerated over a longer period of time compared to the rifle. This results in a greater change in velocity for the bullet, and therefore a greater increase in kinetic energy. Since kinetic energy is directly proportional to the square of the velocity, the bullet ends up with more energy than the recoiling rifle.Rate this question:
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- 6.
An object that has kinetic energy must be _____.
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Moving.
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Falling.
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At an elevated position.
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At rest.
Correct Answer
A. Moving.Explanation
An object that has kinetic energy must be moving because kinetic energy is the energy possessed by an object due to its motion. Kinetic energy depends on the mass and velocity of the object, and it is directly proportional to the square of the velocity. Therefore, if an object is stationary or at rest, it does not have any kinetic energy.Rate this question:
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- 7.
An object that has potential energy has this energy because of its _____.
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Speed.
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Acceleration.
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Momentum.
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Location.
Correct Answer
A. Speed.Explanation
An object that has potential energy has this energy because of its speed. Potential energy is the energy possessed by an object due to its position or condition. In the case of speed, an object with high speed has a greater potential energy because it has the ability to do more work or cause more change. The speed of an object directly affects its potential energy, making it the correct answer in this context.Rate this question:
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- 8.
An object is raised above the ground gaining a certain amount of potential energy. If the same object is raised twice as high it gains _____.
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Four times as much potential energy.
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Twice as much potential energy.
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Half as much potential energy
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Neither of these.
Correct Answer
A. Twice as much potential energy.Explanation
When an object is raised above the ground, it gains potential energy due to its increased height. The potential energy is directly proportional to the height of the object. Therefore, if the object is raised twice as high, it will gain twice as much potential energy. This is because the potential energy is directly proportional to the height, so increasing the height by a factor of 2 will result in an increase in potential energy by the same factor of 2.Rate this question:
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- 9.
When an object is lifted 10 meters, it gains a certain amount of potential energy. If the same object is lifted 20 meters, its potential energy is ______.
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Less.
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The same
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Twice as much.
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Four times as much
Correct Answer
A. Twice as much.Explanation
When an object is lifted, its potential energy is directly proportional to the height it is lifted to. Therefore, if the object is lifted 20 meters instead of 10, its potential energy will be twice as much. This is because potential energy is calculated using the formula PE = mgh, where m is the mass of the object, g is the acceleration due to gravity, and h is the height. As the height is doubled, the potential energy will also double.Rate this question:
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- 10.
Two identical arrows, one with twice the kinetic energy of the other, are fired into a hay bale. The faster arrow will penetrate _____.
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The same distance as the slower arrow.
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Twice as far as the slower arrow.
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Four times as far as the slower arrow.
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More than four times as far as the slower arrow.
Correct Answer
A. Twice as far as the slower arrow.Explanation
The kinetic energy of an object is directly proportional to its velocity squared. Since the faster arrow has twice the kinetic energy of the slower arrow, it means that its velocity is square root of 2 times greater than the velocity of the slower arrow. The distance penetrated by an arrow is directly proportional to its velocity. Therefore, the faster arrow will penetrate twice as far as the slower arrow.Rate this question:
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- 11.
A ball is projected into the air with 100 J of kinetic energy which is transformed to gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, its kinetic energy is _____.
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Less than 100 J.
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More than 100 J.
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100 J.
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Not enough information given.
Correct Answer
A. Less than 100 J.Explanation
When the ball is projected into the air, it has 100 J of kinetic energy. As it reaches the top of its trajectory, this kinetic energy is completely transformed into gravitational potential energy. However, when the ball returns to its original level, it encounters air resistance which causes some of its energy to be lost. Therefore, its kinetic energy when it returns to its original level is less than the initial 100 J.Rate this question:
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- 12.
Strictly speaking, a car will burn more gasoline if the car radio is turned on. This statement is _____.
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Totally false.
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True only if the car's engine is running.
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True only if the car's engine is stopped.
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Always true.
Correct Answer
A. Always true.Explanation
The explanation for the given correct answer, "always true," is that the car radio requires electrical power to operate, which is generated by the car's engine. Therefore, regardless of whether the car's engine is running or stopped, the car radio will consume gasoline because the engine needs to be running to provide the necessary power. Hence, it is always true that a car will burn more gasoline if the car radio is turned on.Rate this question:
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- 13.
Two identical arrows, one with twice the speed of the other, are fired into a hay bale. The faster arrow will penetrate _____.
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The same distance as the slower arrow.
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Twice as far as the slower arrow.
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Four times as far as the slower arrow.
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More than four times as far as the slower arrow.
Correct Answer
A. Four times as far as the slower arrow.Explanation
The faster arrow will penetrate four times as far as the slower arrow because the kinetic energy of an object is directly proportional to its velocity squared. Since the faster arrow has twice the speed of the slower arrow, it will have four times the kinetic energy. This increased energy will allow it to penetrate the hay bale four times deeper than the slower arrow.Rate this question:
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- 14.
How many Joules of energy are in one kilowatt-hour?
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1 J
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60 J
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60 kilojoules
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3.6 megajoules
Correct Answer
A. 3.6 megajoulesExplanation
One kilowatt-hour is equal to 3.6 megajoules. This conversion can be done by multiplying the number of kilowatt-hours by 3.6. Since a kilowatt-hour is a unit of energy and a joule is also a unit of energy, the conversion between the two can be made. Therefore, the correct answer is 3.6 megajoules.Rate this question:
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- 15.
A feather and a coin dropped in a vacuum fall with equal _____.
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Forces
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Momenta
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Accelerations
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Kinetic energies
Correct Answer
A. AccelerationsExplanation
In a vacuum, there is no air resistance or other external forces acting on the feather and the coin. Therefore, both objects experience the same gravitational force and fall with the same acceleration. This means that their accelerations are equal.Rate this question:
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Current Version
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Mar 22, 2023Quiz Edited by
ProProfs Editorial Team -
Jan 10, 2013Quiz Created by
Rajashreebasu
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