Science Physical Science Flashcards

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?

Answer: 500 J

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

Which of the following best describes a conductor?

Answer: A material that allows electric current to flow easily

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

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

Answer: One-fourth as great

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

Which phase change occurs when a liquid becomes a gas?

Answer: Evaporation

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

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

Answer: Strongly acidic

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

Which of the following is an example of a chemical change?

Answer: Iron rusting

Rusting is a chemical change because iron reacts with oxygen and water to form a new substance, iron oxide.

Sound travels fastest through which medium?

Answer: Steel

Sound travels fastest through solids like steel because particles are more closely packed, allowing faster transmission of vibrations.