Gravity and Orbits

What role does inertia play in planetary motion?

• Inertia keeps planets moving in a straight line unless acted upon by gravity.

• Inertia has no effect on planetary motion.

• Inertia pulls planets towards the sun.

What is the relationship between mass and gravitational force?

• The greater the mass of an object, the stronger its gravitational pull.

• Mass has no effect on gravitational force.

• Gravitational force decreases with increasing mass.

• Only large masses exert gravitational force.

What are astronomical units used for?

• Distances within a solar system.

• Calculating the speed of light.

• Determining the age of stars.

How does gravity affect the motion of planets?

• Gravity keeps planets in orbit around the sun.

• Gravity causes planets to collide with each other.

• Gravity makes planets move in a straight line.

• Gravity has no effect on the motion of planets.

Does an object's mass change?

• No, an object's mass never changes.

• Yes, an object's mass changes with temperature.

• No, an object's mass changes only when it is in motion.

What is the shape of most planetary orbits?

• Elliptical

• Parabolic

• Hyperbolic

What is the definition of mass?

• The weight of an object in a vacuum.

• The volume of an object measured in liters.

• The density of an object calculated by mass divided by volume.

A longer orbit.

• A shorter day

• A longer year

• A faster rotation

• A smaller planet

What is inertia?

• The force that causes an object to move in a circular path.

• The tendency of an object to resist a change in motion (if still, it will stay still, or if moving it will keep moving).

• The speed at which an object travels in a straight line.

• The gravitational pull that affects an object's weight.

What is matter?

• A substance that cannot be seen or touched.

• A type of energy that exists in various forms.

• A concept that describes the absence of physical substance.