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6. Gravity is the universal force of attraction between masses. How does the mass of an object affect its gravitational force of attraction?

  • The smaller the mass of the object, the greater the gravitational force of attraction.
  • The greater the mass of the object, the greater the gravitational force of attraction.
  • The mass of an object doesn't affect its gravitational force of attraction.
  • The greater the mass of the object, the weaker the gravitational force of attraction.

7. Satellites in low polar orbit pass over the poles and orbit the Earth 100-200km from its surface. How long is their orbital period?

  • 120 minutes
  • 90 minutes
  • 60 minutes
  • 30 minutes

8. The forward motion preventing Earth's gravitational pull from making a satellite fall to its surface is called:

  • friction
  • centripetal force
  • tangential motion
  • momentum

9. As a comet nears the Sun, the speed at which it travels in its orbit increases. This is because:

  • the size of the comet increases as it gets closer to the Sun
  • as the comet nears the Sun, the gravitational force of attraction between the comet and the Sun is greater
  • as the comet nears the Sun, the gravitational force of attraction between the comet and the Sun is greater
  • when the comet is further away from the Sun, the gravitational force of attraction between the comet and the Sun is greater

10. The particular height of the orbit of a geostationary satellite ensures that:

  • the satellite can orbit the Earth much faster than the rate that it is turning
  • the satellite's orbital period is 24 hours long, so it appears stationary when observing from the Earth's surface
  • the satellite is able to pass over the entire surface of the Earth, as the Earth continues to turn whilst the satellite orbits
  • the satellite remains stationary

11. How does the tangential motion of a satellite orbiting Earth affect its trajectory?

  • It doesn't.
  • If the tangential motion of the satellite is too slow, it will fall to the Earth's surface. If the tangential motion of the satellite is too fast, it will travel away from Earth and into space.
  • If the tangential motion of the satellite is too slow, it will travel away from the Earth and into space. If the tangential motion of the satellite is too fast, it will fall to the Earth's surface.
  • The tangential motion of a satellite affects its speed, not its trajectory.

12. Satellites in low polar orbit are closer to the Earth's surface. This means that a higher gravitational force of attraction is present between the satellite and the Earth. Does this affect the tangential speed required to keep a satellite in orbit?

  • Yes, because the small distance between the Earth and the satellite produces a high centripetal acceleration. A high tangential speed is required.
  • Yes, because the small distance between the Earth and the satellite produces a high centripetal acceleration. A low tangential speed is required.
  • Yes, because the small distance between the Earth and the satellite produces a low centripetal acceleration. The tangential speed must be high.
  • No, because the distance between the Earth and the satellite will not affect the centripetal acceleration of the satellite. Any tangential speed can be applied and it will not affect the satellite's trajectory.

13. The force between two objects increases as the distance between them decreases. This is an inverse square law. If the distance between two objects is enlarged by a scale factor of ten, what happens to the force between them?

  • It decreases to one millionth of what it was originally
  • It decreases to one hundredth of what it was originally
  • It decreases to one thousandth of what it was originally
  • It decreases to one tenth of what it was originally

14. Gravity provides something, without which objects such as planets would not orbit their stars and instead move away at a tangent. What is it that gravity provides that prevents this from happening?

  • Friction
  • Centripetal force
  • Momentum
  • Tangential motion

15. When a satellite is orbiting the Earth, how does its distance from the Earth affect the speed of its orbit?

  • The closer to the Earth's surface a satellite is, the faster it travels. The further away from the Earth's surface a satellite is, the slower it travels.
  • The closer to the Earth's surface a satellite is, the faster it travels. The further away from the Earth's surface a satellite is, the faster it travels.
  • The closer to the Earth's surface a satellite is, the slower it travels. The further away from the Earth's surface a satellite is, the faster it travels.
  • The distance from the Earth's surface to a satellite doesn't affect the speed of the satellite's orbit.