1. What is gravity?

• A force that repels all objects with mass

• An attractive force between objects with mass

• A type of light energy.

• The reason objects float in space.

What happens as the mass of an object increases?

• It becomes lighter.

• It moves faster.

• Its gravitational pull gets stronger.

• It loses energy.

What was the solar system before it formed?

• A cluster of stars.

• A large planet.

• A huge cloud of dust and gases.

• A frozen comet.

What happened when particles in the cloud stuck together?

• They disappeared.

• They formed light.

• They turned into water.

• They formed a larger mass with stronger gravity.

What did the spinning collapsed cloud become?

• A single star

• A flat disk of particles and gas

• A stationary gas ball

• A black hole

What caused part of the dust cloud to collapse?

• Unknown, but the collapse began the formation.

• An asteroid impact

• Magnetic fields

• Sunlight

How did the sun form from the cloud?

• By atoms combining and releasing energy

• By collecting water molecules

• Through an earthquake in space

• Through volcanic activity

What happened to the leftover particles after the sun formed?

• They were burned up

• They vanished

• They formed another sun

• They clumped together to form planets and other objects

Why do planets stay in orbit around the sun?

• Because of their temperature

• Because of a balance between gravity and momentum

• Due to strong winds in space

• Because the sun pushes them

What prevents planets from falling into the sun?

• Their sideways momentum

• A magnetic force

• Friction in space

• Their low temperature