Understanding Energy Concepts

What is the formula for calculating work?

• Work = Force × Distance × cos(θ)

• Work = Mass × Acceleration

• Work = Energy × Time

• Work = Force + Distance

Define kinetic energy and provide an example.

• Kinetic energy is the energy stored in an object at rest; for example, a stationary boulder.

• Kinetic energy is the energy of an object due to its temperature; for example, a hot cup of coffee.

• Kinetic energy is the energy of an object in motion; for example, a moving car.

• Kinetic energy is the energy released during a chemical reaction; for example, burning wood.

What is the unit of power?

• ohm

• joule

• watt

• volt

How is potential energy different from kinetic energy?

• Potential energy is the energy of sound waves.

• Kinetic energy is stored energy based on position.

• Potential energy is stored energy based on position; kinetic energy is energy of motion.

• Potential energy is always greater than kinetic energy.

State the Law of Conservation of Energy.

• Energy can be created and destroyed.

• Energy cannot be created or destroyed, only transformed.

• Energy is always lost in transformations.

• Energy can only be created from matter.

If a force of 10 N moves an object 5 m, how much work is done?

• 25 J

• 50 J

• 40 J

• 75 J

What is the relationship between work and energy?

• Work is a form of energy storage.

• Work is the same as energy.

• Energy can exist without work.

• Work is the transfer of energy.

Calculate the power if 100 J of work is done in 5 seconds.

• 15 W

• 50 W

• 20 W

• 25 W

Explain how energy can change forms with an example.

• A battery stores kinetic energy for later use.

• An example of energy changing forms is a roller coaster, where potential energy at the top converts to kinetic energy as it descends.

• A car engine transforms thermal energy into chemical energy.

• A light bulb converts electrical energy into sound energy.

What happens to energy in a closed system according to the Law of Conservation?

• Energy can be freely exchanged with the environment in a closed system.

• Energy is created and destroyed in a closed system.

• Energy is conserved and can only change forms in a closed system.

• Energy can only be lost in a closed system.