Exploring Work and Energy Concepts

What is the formula to calculate work done?

• Work = Force + Distance

• Work = Distance x Time

• Work = Force x Distance x cos(θ)

• Work = Force / Distance

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

• 75 J

• 25 J

• 50 J

• 40 J

What is energy transfer? Give an example.

• An example of energy transfer is a car moving on a road.

• Energy transfer occurs when a light bulb is turned off.

• An example of energy transfer is heat moving from a hot stove to a pot of water.

• Energy transfer is the process of making toast in a toaster.

List three different forms of energy.

• Sound energy

• Chemical energy

• Nuclear energy

• Kinetic energy, potential energy, thermal energy

Explain the principle of conservation of energy.

• Energy is only lost in transformations.

• Energy can be created from nothing.

• Total energy in a closed system can change over time.

• Energy cannot be created or destroyed, only transformed; total energy in a closed system remains constant.

If a ball is dropped from a height, what happens to its potential energy?

• The potential energy decreases as the ball falls.

• The potential energy increases as the ball falls.

• The potential energy remains constant throughout the fall.

• The potential energy is converted entirely to kinetic energy before hitting the ground.

How do you calculate the kinetic energy of an object?

• KE = 0.5 * m * v^2

• KE = m * v

• KE = 0.5 * m * v

• KE = m * v^2 / 2

A roller coaster at the top of a hill has potential energy. What happens to that energy as it goes down?

• The potential energy is lost completely as it descends.

• The potential energy increases as it goes down.

• The potential energy turns into thermal energy immediately.

• The potential energy is converted into kinetic energy as it goes down.

Interpret the energy diagram of a pendulum. What happens at the highest and lowest points?

• At the highest points, both potential and kinetic energy are equal; at the lowest point, both energies are zero.

• At the highest points, potential energy is minimum and kinetic energy is maximum; at the lowest point, both energies are equal.

• At the highest points, potential energy is maximum and kinetic energy is minimum; at the lowest point, potential energy is minimum and kinetic energy is maximum.

• At the highest points, kinetic energy is maximum and potential energy is minimum; at the lowest point, potential energy is maximum and kinetic energy is minimum.

Solve the work-energy problem: A car does 2000 J of work to accelerate. If its mass is 1000 kg, what is its final speed?

• 4 m/s

• 3 m/s

• 1 m/s

• 2 m/s