AP Physics Work-Energy Quick Review

Front

What is Kinetic Energy?

Back

Kinetic Energy is defined as the energy of motion.

Front

How is Kinetic Energy calculated?

Back

Kinetic Energy (KE) = 1/2 * m * v², where m is mass and v is velocity.

Front

Which object has the most kinetic energy? A 20 kg toddler running at 5 m/s, A 50 kg toddler running at 30 m/s, A 90 kg toddler running at 30 m/s, A 100 kg toddler running at 2 m/s?

Back

A 90 kg toddler running at 30 m/s has the most kinetic energy.

Front

What is the relationship between work and energy?

Back

The work done by an external force acting on an object causes a change in the mechanical energy of the object.

Front

How much work is done by a net force of 1000 N moving an object 5 m?

Back

Work = Force * Distance = 1000 N * 5 m = 5000 J.

Front

What is the formula for calculating work?

Back

Work (W) = Force (F) * Distance (d) * cos(θ), where θ is the angle between the force and the direction of motion.

Front

What is the unit of work in the SI system?

Back

The unit of work is the Joule (J).

Front

If a 40 kg crate is lifted to a height of 50 m, what is the potential energy gained?

Back

Potential Energy (PE) = m * g * h = 40 kg * 9.8 m/s² * 50 m = 19600 J.

Front

What happens to the potential energy of an object as it falls?

Back

As an object falls, its potential energy is converted into kinetic energy.

Front

What is the velocity of a crate just before it hits the ground if it falls from a height of 50 m?

Back

The velocity just before it hits the ground is approximately 31.3 m/s.