Usaha dan Energi

What is the Law of Conservation of Energy?

• Energy can only be created from matter.

• Energy is a fixed quantity that cannot change.

• Energy cannot be created or destroyed, only transformed.

• Energy can be created and destroyed.

How does energy change forms in a closed system?

• Energy can only exist as kinetic energy in a closed system.

• Energy can be created or destroyed in a closed system.

• Energy remains unchanged in form and quantity.

• Energy changes forms through conversion and transformation while total energy remains constant.

Define work in the context of physics.

• Work is the speed at which an object moves.

• Work is the energy transferred when a force is applied to an object over a distance.

• Work is the amount of force applied to an object.

• Work is the total energy stored in an object.

What is the formula for calculating work?

• Work = Distance / Time

• Work = Force × Distance × cos(θ)

• Work = Force / Distance

• Work = Force + Distance

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

• 25 J

• 50 J

• 40 J

• 75 J

Explain the relationship between work and energy.

• Work and energy are directly related; work done on an object results in a change in its energy.

• Energy can exist without any work being done.

• Work is unrelated to energy and does not affect it.

• Work is a form of energy that cannot change an object's state.

What is kinetic energy and how is it calculated?

• Kinetic energy is the energy of an object at rest.

• Kinetic energy is calculated using the formula KE = m * v.

• Kinetic energy is calculated using the formula KE = 0.5 * m * v^2.

• Kinetic energy is the energy stored in an object due to its position.

Describe potential energy and give an example.

• A stretched rubber band has no potential energy until released.

• An example of potential energy is a rock positioned at the top of a hill; it has gravitational potential energy due to its height.

• A car moving at high speed has potential energy due to its motion.

• A fish swimming in water has potential energy because it is in a liquid environment.

How does friction affect the work done on an object?

• Friction only affects the speed of an object, not the work done.

• Friction increases the total work done on an object by adding energy.

• Friction has no effect on the work done on an object.

• Friction reduces the net work done on an object by converting some of the work into heat.

What is the unit of energy in the International System of Units?

• watt

• calorie

• joule

• volt