Work and Energy Concepts

What is the formula for calculating kinetic energy?

• KE = m / v

• KE = 0.5 * m + v

• KE = 0.5 * m * v^2

• KE = m * v^2

Define potential energy and provide an example.

• Potential energy is the energy an object has due to its position relative to other objects. It is stored energy that can be converted into other forms. For example, a ball held above the ground has gravitational potential energy.

• Potential energy is the energy an object has due to its speed

• Potential energy is the energy an object has due to its color

• Potential energy is the energy an object has due to its temperature

State the work-energy theorem and explain its significance.

• The work-energy theorem is only applicable to non-mechanical systems

• The work-energy theorem is used to calculate gravitational force

• The work-energy theorem is significant as it provides a direct relationship between work and energy, allowing for the analysis of mechanical systems and the prediction of their behavior.

• The work-energy theorem states that energy is not conserved in mechanical systems

How is mechanical energy conserved in a system?

• By increasing the temperature of the system

• By introducing friction into the system

• By changing the shape of the system

• By having no external work done on the system and no non-conservative forces present.

What is power in the context of work and energy?

• Power is the distance over which work is done.

• Power is the amount of energy stored in a system.

• Power is the speed at which work is completed.

• Power is the rate at which work is done or energy is transferred.

Calculate the kinetic energy of an object with a mass of 5 kg and a velocity of 10 m/s.

• 150 J

• 250 J

• 100 J

• 50 J

Give an example of an object with high potential energy.

• stretched rubber band

• dropped book

• deflated balloon

• compressed spring

Explain the concept of conservative forces in relation to potential energy.

• Conservative forces in relation to potential energy are forces that are path-independent and can be associated with a potential energy function.

• Conservative forces are always dependent on the path taken

• Potential energy is not related to conservative forces

• Conservative forces are always dissipative

How does friction affect the conservation of mechanical energy?

• Friction has no effect on the conservation of mechanical energy

• Friction converts mechanical energy into other forms, leading to a decrease in the total mechanical energy of the system.

• Friction increases the total mechanical energy of the system

• Friction only affects the kinetic energy of the system

Calculate the work done when a force of 20 N is applied to move an object 5 meters.

• 50 J

• 100 J

• 120 J

• 80 J