Energy, Work, and Power Quiz

What is the SI unit for kinetic energy?

• Watt

• Joule

• Calorie

• lbf ft

Answer explanation

The SI unit for kinetic energy is Joule. Joule is the unit of energy in the International System of Units (SI) and is defined as the work done by a force of one newton acting over a distance of one meter.

What type of energy is stored in a stretched spring?

• Elastic Energy

• Kinetic Energy

• Thermal Energy

• Potential Energy

Answer explanation

The correct type of energy stored in a stretched spring is Elastic Energy, which is potential energy stored in the spring due to its deformation.

How does heat transfer between objects?

• From a low-temperature region to a high-temperature region

• Only in a vacuum

• From a high-temperature region to the low-temperature region

• Equally in all directions regardless of temperature

Answer explanation

Heat transfers from a high-temperature region to a low-temperature region, following the direction of the temperature gradient.

What does the first law of thermodynamics state?

• The entropy of the universe is constant

• Energy cannot be created or destroyed

• Total mechanical energy of a system is constant if no heat transfer occurs

• Net heat transfer to the system minus the work done by the system equals the change in total energy of the system

Answer explanation

The first law of thermodynamics states that net heat transfer to the system minus the work done by the system equals the change in total energy of the system.

What is the U.S. Customary unit of power?

• Watt

• lbf ft

• lbf ft/s

• Joule

Answer explanation

The U.S. Customary unit of power is lbf ft/s, which represents the foot-pound force per second, commonly used in the United States to measure power.

What is the thermal efficiency of a typical gasoline engine?

• Approximately 40 to 45%

• Approximately 55 to 60%

• Approximately 10 to 15%

• Approximately 25 to 30%

Answer explanation

The correct answer is approximately 25 to 30% as the thermal efficiency of a typical gasoline engine falls within this range.

What is the definition of efficiency?

• Efficiency = required input / actual output

• Efficiency = heat input / power output

• Efficiency = actual output / required input

• Efficiency = power output / heat input

Answer explanation

Efficiency is defined as the actual output divided by the required input, making the correct answer choice Efficiency = actual output / required input.

What represents the amount of thermal energy needed to raise the temperature of one pound mass of water by one degree Fahrenheit?

• Joule

• British thermal unit (Btu)

• Calorie

• Watt

Answer explanation

The correct choice is British thermal unit (Btu) which represents the amount of thermal energy needed to raise the temperature of one pound mass of water by one degree Fahrenheit.

What is the power requirement formula?

• Power = work / time

• Power = energy / time

• Power = time / work

• Power = work / energy

Answer explanation

The correct formula for power requirement is Power = work / time. This formula defines power as the amount of work done per unit of time.

What happens to the kinetic energy of a car when it comes to a stop?

• It remains constant

• It is converted into another form of energy

• It is completely lost as heat

• It is converted into potential energy

Answer explanation

When a car comes to a stop, its kinetic energy is converted into another form of energy, such as heat or sound.