Motion in space

What is the difference between mass and weight?

• Weight is the same on the moon as on Earth, but mass changes.

• Mass is a measure of how much matter makes something up, while weight is a measure of the pull of gravity on an object.

• Mass changes depending on the gravitational field strength, while weight does not.

• Mass is measured in Newtons and weight in kilograms.

What is centripetal force?

• The force that keeps an object at rest.

• The force that pushes a moving object away from the center of its curved path.

• The force that pulls a moving object toward the center of its curved path.

• A measure of the gravitational pull on an object.

Why does an object moving in a circle accelerate?

• Because the centripetal force decreases.

• Because its speed is increasing.

• Because it is moving away from the gravitational pull.

• Because its direction is continually changing.

What happens if the centripetal force on an object moving in a circle is removed?

• The object will stop moving.

• The object will move in a larger circle.

• The object will move towards the center of the circle.

• The object will move off in a straight line.

What keeps the planets in orbit?

• The sun's gravity applying a centripetal force.

• The lack of gravitational pull in space.

• Their velocity.

• Their mass.

What is the role of gravity in the motion of comets, moons, satellites, and space stations?

• It propels them into space.

• It decreases their mass.

• It holds them in orbit.

• It changes their shape.

What is a satellite?

• A comet traveling through space.

• A planet orbiting the sun.

• A type of star.

• Any object that orbits around another object.

What is the purpose of communications satellites?

• To study Earth's surface.

• To forecast weather.

• To act as relay stations in space for messages.

• To navigate ships at sea.

What type of orbit does a satellite in geostationary equatorial orbit have?

• It orbits in a north-south direction.

• It takes the satellite 12 hours to circle the planet.

• It stays directly over the same spot on Earth.

• It orbits close to Earth's surface.

How do satellites in Low Earth Orbit (LEO) maintain their orbit without falling back into the atmosphere?

• By increasing their mass.

• By staying stationary.

• By traveling very fast.

• By orbiting at a slow speed.