Energy and Work

Description: This quiz covers the fundamental concepts of energy and work in physics. Test your understanding of energy forms, work-energy theorem, and related principles.
Number of Questions: 15
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Tags: energy work energy forms work-energy theorem kinetic energy potential energy conservation of energy
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Which of the following is NOT a form of energy?

  1. Heat

  2. Light

  3. Mass

  4. Motion


Correct Option: C
Explanation:

Mass is a property of matter, not a form of energy.

The SI unit of energy is:

  1. Joule

  2. Watt

  3. Newton

  4. Kelvin


Correct Option: A
Explanation:

The joule (J) is the SI unit of energy, named after James Prescott Joule.

What is the work done by a force when an object is displaced?

  1. Force × Displacement

  2. Force × Velocity

  3. Force × Acceleration

  4. Force × Time


Correct Option: A
Explanation:

Work is defined as the product of force and displacement in the direction of the force.

The work-energy theorem states that:

  1. Work done on an object equals its change in kinetic energy

  2. Work done on an object equals its change in potential energy

  3. Work done on an object equals its change in total energy

  4. Work done on an object equals its change in momentum


Correct Option: C
Explanation:

The work-energy theorem states that the net work done on an object is equal to its change in total energy (kinetic + potential).

Kinetic energy is the energy of an object due to:

  1. Its mass

  2. Its velocity

  3. Its position

  4. Its temperature


Correct Option: B
Explanation:

Kinetic energy is the energy of motion and depends on the mass and velocity of the object.

Potential energy is the energy of an object due to:

  1. Its mass

  2. Its velocity

  3. Its position

  4. Its temperature


Correct Option: C
Explanation:

Potential energy is the energy stored in an object due to its position or configuration.

The law of conservation of energy states that:

  1. Energy can be created or destroyed

  2. Energy can be transferred from one form to another

  3. The total amount of energy in the universe is constant

  4. Energy can be converted from one form to another with 100% efficiency


Correct Option: C
Explanation:

The law of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed from one form to another.

In a simple harmonic motion, the total mechanical energy of the system is:

  1. Constant

  2. Increasing

  3. Decreasing

  4. Zero


Correct Option: A
Explanation:

In a simple harmonic motion, the total mechanical energy (kinetic + potential) remains constant throughout the motion.

Which of the following is an example of work being done?

  1. Lifting a book

  2. Holding a book

  3. Thinking about lifting a book

  4. Dropping a book


Correct Option: A
Explanation:

Work is done when a force is applied to an object and the object moves in the direction of the force.

A 10 kg object is lifted vertically at a constant speed of 2 m/s through a height of 5 meters. How much work is done?

  1. 100 J

  2. 200 J

  3. 300 J

  4. 400 J


Correct Option: A
Explanation:

Work done = Force × Displacement = (10 kg × 9.8 m/s²) × 5 m = 100 J.

A ball is thrown vertically upward with a velocity of 10 m/s. What is its kinetic energy at the highest point of its trajectory?

  1. 0 J

  2. 50 J

  3. 100 J

  4. 200 J


Correct Option: A
Explanation:

At the highest point of its trajectory, the ball's velocity is zero, so its kinetic energy is zero.

A spring is stretched by 10 cm from its equilibrium position. If the spring constant is 100 N/m, how much potential energy is stored in the spring?

  1. 0.5 J

  2. 1 J

  3. 1.5 J

  4. 2 J


Correct Option: A
Explanation:

Potential energy stored in a spring = (1/2)kx², where k is the spring constant and x is the displacement from equilibrium.

A pendulum swings from one extreme position to another. At which point does it have maximum kinetic energy?

  1. At the highest point

  2. At the lowest point

  3. At the midpoint of its swing

  4. At all points


Correct Option: B
Explanation:

At the lowest point of its swing, the pendulum has maximum velocity and hence maximum kinetic energy.

A 100 kg object is at rest on a horizontal surface. A force of 50 N is applied to the object for 10 seconds. What is the work done on the object?

  1. 500 J

  2. 1000 J

  3. 1500 J

  4. 2000 J


Correct Option: A
Explanation:

Work done = Force × Displacement = 50 N × 0 m = 0 J.

A 2000 kg car is moving at a speed of 30 m/s. What is its kinetic energy?

  1. 90 kJ

  2. 180 kJ

  3. 270 kJ

  4. 360 kJ


Correct Option: A
Explanation:

Kinetic energy = (1/2)mv², where m is the mass and v is the velocity.

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