GED Science Physical Science 3

Question 1

A skateboarder at the top of a ramp has potential energy of 500 J. At the bottom of the ramp, assuming no friction, what is the skateboarder's kinetic energy?

Accepted Answer

500 J

Answer

By conservation of energy, all potential energy converts to kinetic energy when there is no friction.

Question 2

Which of the following best describes a conductor?

Accepted Answer

A material that allows electric current to flow easily

Answer

Conductors have loosely held electrons that allow electric current to pass through them easily.

Question 3

Two objects attract each other gravitationally. If the distance between them is doubled, the gravitational force between them becomes:

Accepted Answer

One-fourth as great

Answer

Newton's law of gravitation states force is inversely proportional to the square of the distance, so doubling distance reduces force to 1/4.

Question 4

Which phase change occurs when a liquid becomes a gas?

Accepted Answer

Evaporation

Answer

Evaporation (or vaporization) is the phase change from liquid to gas.

Question 5

A substance has a pH of 2. This substance is best described as:

Accepted Answer

Strongly acidic

Answer

A pH of 2 is well below 7, placing it in the strongly acidic range of the pH scale.

GED Practice Test

GED Practice Test

GED Science Physical Science 3