Energy, Work and Power

Front

What is the definition of kinetic energy?

Back

Kinetic energy is the energy that an object possesses due to its motion, calculated as KE = 1/2 mv², where m is mass and v is velocity.

Front

How is work defined in physics?

Back

Work is defined as the energy transferred to or from an object via the application of force along a displacement, calculated as Work = Force x Distance.

Front

What is the formula for calculating power?

Back

Power is defined as the rate at which work is done or energy is transferred, calculated as Power = Work / Time.

Front

What is the unit of power in the International System of Units (SI)?

Back

The unit of power in the SI system is the Watt (W), which is equivalent to one joule per second.

Front

How much energy does a 75W light bulb consume in 1 hour?

Back

A 75W light bulb consumes 270,000 joules (or 270 kJ) in 1 hour, calculated as Energy = Power x Time = 75W x 3600s.

Front

What happens to kinetic energy if the velocity of an object is doubled?

Back

If the velocity of an object is doubled, its kinetic energy increases by a factor of four, since KE = 1/2 mv².

Front

What is the relationship between work and energy?

Back

Work is a means of transferring energy from one system to another; when work is done on an object, energy is transferred to that object.

Front

How do you calculate the work done by a force?

Back

Work done by a force can be calculated using the formula Work = Force x Distance x cos(θ), where θ is the angle between the force and the direction of motion.

Front

What is the significance of the angle in the work formula?

Back

The angle θ in the work formula determines how much of the force contributes to the work done; if θ is 0°, all the force contributes, while at 90°, none does.

Front

What is the principle of conservation of energy?

Back

The principle of conservation of energy states that energy cannot be created or destroyed, only transformed from one form to another.