Kinetic and Potential Energy Stores

Question 1

What is the energy in an object’s kinetic energy store dependent on?

Answer 1

The object’s mass and speed

The greater the mass and speed, the more energy in the kinetic energy store.

Question 2

What happens to energy in the kinetic energy store when an object speeds up?

Answer 2

Energy is transferred to this store

This occurs as the object’s speed increases.

Question 3

What happens to energy in the kinetic energy store when an object slows down?

Answer 3

Energy is transferred away from this store

This occurs as the object’s speed decreases.

Question 4

What is the formula for calculating kinetic energy?

Answer 4

Ek = 1/2 mv²

Where E is kinetic energy, m is mass, and v is speed.

Question 5

Calculate the kinetic energy of a car with a mass of 2500 kg traveling at 20 m/s.

Answer 5

500,000 J

Using the formula E = 1/2 mv²: E = 1/2 * 2500 * (20)².

Question 6

What is gravitational potential energy dependent on?

Answer 6

The object’s mass, height, and the strength of the gravitational field

More height means more energy transferred to the gravitational potential energy store.

Question 7

What is the formula for gravitational potential energy?

Answer 7

Ep = mgh

Where Ep is gravitational potential energy, m is mass, g is gravitational field strength, and h is height.

Question 8

What happens to energy when an object falls?

Answer 8

Energy from its gravitational potential energy store is transferred to its kinetic energy store

This occurs when there is no air resistance.

Question 9

True or False: Energy lost from the gravitational potential energy store equals energy gained in the kinetic energy store for falling objects without air resistance.

Answer 9

True

This principle holds when ignoring air resistance.

Question 10

What effect does air resistance have on falling objects?

Answer 10

It causes some energy to be transferred to other energy stores

Examples include thermal energy stores of the object and surroundings.

Question 11

What type of energy store is created when stretching or squashing an object?

Answer 11

Elastic potential energy store

This occurs when energy is transferred to the object during deformation.

Question 12

What is the formula for elastic potential energy?

Answer 12

Ee = 1/2 ke²

Where E is elastic potential energy, k is the spring constant, and e is the extension.

Question 13

What must not be exceeded for energy to remain in the elastic potential energy store?

Answer 13

The limit of proportionality

Exceeding this limit can lead to permanent deformation.