Gravity in Space

What causes the sensation of weightlessness for astronauts in orbit?

• Astronauts are far from Earth's surface where gravitation has minimal effect.

• They are in free fall and so there are no external contact forces acting upon their body.

• There is no gravity in space.

• Space is a vacuum and there is no air resistance.

What type of force is gravity considered as?

• A contact force

• An action-at-a-distance force

• A normal force

• A frictional force

What is true about weightlessness?

• It is experienced when all contact forces are removed and objects are in free fall.

• It occurs only in space.

• It means an individual has lost weight.

• It is a sensation experienced when there are external objects touching one's body.

Why do astronauts orbiting Earth still experience gravity?

• Because gravity acts over a distance through space

• Because they are moving at a constant speed

• Because of air resistance

• Because they are in a vacuum

What is the force of gravity at an altitude of approximately 400 km above Earth's surface compared to on Earth's surface?

• Significantly less, almost zero

• Slightly less

• Greater

• The same

What is the misconception about gravity and air?

• Gravity can only act where there is air

• Gravity is stronger in a vacuum

• Gravity does not exist in a vacuum

• Air pressure affects gravity

What provides the force that keeps an astronaut circling around the earth in orbit (rather than moving forward in a straight line)?

• The astronaut's speed

• The force of gravity

• The lack of air resistance

• The vacuum of space

What happens to the force of gravity acting on an astronaut in orbit compared to on Earth?

• It increases significantly

• It decreases slightly

• It remains the same

• It becomes zero

Why do orbiting astronauts feel weightless?

• Because they are moving at high speeds

• Because they are inside a spacecraft

• Because they are far from Earth

• Because they are in free fall with no other forces acting on them other than gravity.

What is the effect of air pressure on the force of gravity?

• It makes the force of gravity act over larger distances

• It has no effect on the force of gravity

• It decreases the force of gravity

• It increases the force of gravity