Practice Set | Unit 2 - Types of Energy

What is kinetic energy?

• Energy stored in an object due to its position

• Energy an object possesses due to its motion

• Energy stored in chemical bonds

• Energy released during nuclear reactions

Answer explanation

Kinetic energy is defined as the energy an object possesses due to its motion. This distinguishes it from potential energy, which is related to an object's position, and other forms of energy like chemical or nuclear energy.

Tags

NGSS.HS-PS3-2

Which of the following factors has a greater impact on the kinetic energy of an object?

• Mass

• Velocity

• Temperature

• Volume

Answer explanation

Kinetic energy is given by the formula KE = 1/2 mv². While mass affects kinetic energy, velocity has a squared relationship, meaning small changes in velocity result in larger changes in kinetic energy, making it the greater factor.

Tags

NGSS.HS-PS3-2

How is kinetic energy transferred between objects?

• Through chemical reactions

• By direct contact or collision

• By gravitational pull

• Through nuclear fusion

Answer explanation

Kinetic energy is transferred between objects primarily by direct contact or collision. When two objects collide, the energy from one object can be transferred to the other, resulting in motion.

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

NGSS.HS-PS3-3

• 3 J

• 6 J

• 9 J

• 18 J

Answer explanation

To find the kinetic energy (KE), use the formula KE = 1/2 mv^2. Plugging in m = 2 kg and v = 3 m/s gives KE = 1/2 * 2 * (3^2) = 1 * 9 = 9 J. Thus, the correct answer is 9 J.

Tags

NGSS.HS-PS3-2

Which of the following is an example of gravitational potential energy?

• A stretched rubber band

• A book on a shelf

• A charged battery

• A lit match

Answer explanation

Gravitational potential energy is the energy stored in an object due to its height above the ground. A book on a shelf has potential energy because it is elevated, while the other options do not involve height.

Identify the type of potential energy stored in a compressed spring.

• Gravitational

• Elastic

• Chemical

• Nuclear

Answer explanation

The potential energy stored in a compressed spring is called elastic potential energy. This energy is due to the deformation of the spring, which can return to its original shape, unlike gravitational, chemical, or nuclear energy.

Which of the following is an example of chemical potential energy?

• A rock at the top of a hill

• A stretched bow

• Gasoline in a car

• A spinning top

Answer explanation

Chemical potential energy is stored in the bonds of chemical compounds. Gasoline in a car contains chemical potential energy that can be released during combustion, making it the correct choice. The other options represent different forms of energy.

What happens at the molecular level when heat is added to a substance?

• Molecules move slower

• Molecules move faster

• Molecules stop moving

• Molecules decrease in size

Answer explanation

When heat is added to a substance, the energy increases, causing molecules to move faster. This increased motion can lead to changes in state, such as melting or boiling, as the kinetic energy of the molecules rises.

Tags

NGSS.MS-PS1-4

Explain the process of conduction.

• Transfer of heat through electromagnetic waves

• Transfer of heat through direct contact

• Transfer of heat through fluid movement

• Transfer of heat through chemical reactions

Answer explanation

Conduction is the transfer of heat through direct contact between materials. When two objects at different temperatures touch, heat flows from the hotter object to the cooler one until thermal equilibrium is reached.

Tags

NGSS.HS-PS3-4

Which form of kinetic energy is demonstrated by a moving car?

• Thermal

• Electrical

• Mechanical

• Sound

Answer explanation

A moving car demonstrates mechanical kinetic energy, which is the energy of motion. Unlike thermal, electrical, or sound energy, mechanical energy specifically refers to the energy associated with the movement of objects.