answers: review quiz on Newton's laws of motion and gravity

  1. An object that is moving with constant velocity
    will tend to continue moving with constant velocity unless a force acts on it (Newton's first law).
  2. An object sliding on ice will slide more distance than an object sliding on a carpet. This means that the tendency of an object to stop moving is a property of the friction force caused by the object it is sliding on.
  3. If the Earth pulls on the baseball, the baseball will pull equally on the Earth.
  4. If the Earth pulls on the baseball, the baseball will not move the same distance as the Earth.
  5. Newton's third law says that if object A exerts a force on object B, then object B exerts a force on object A, which is equal in strength but in the opposite direction.
  6. Newton's second law says (in words): heavier objects are harder to move.
  7. Newton's second law says (as an equation): a = F/m (accelleration = force over mass)
  8. The pull of gravity on heavier objects is more than the pull of gravity on lighter objects.
  9. In a vacuum heavier objects fall the same speed as lighter objects. The reason is because they are harder to move, which cancels out the fact that gravity pulls harder on them.
  10. The moon is more massive than the baseball, so that would tend to make the Earth pull more on the moon. However, the moon is farther away from Earth, so that would tend to make the pull of gravity less.
  11. The acceleration of the moon toward the Earth is smaller than the acceleration of the baseball toward the center of the Earth. The reason is because the moon is farther away; also, it is harder to move because it is more massive than the baseball.
  12. The force of gravity of the Earth pulling on the moon is the same as the force of gravity of the moon pulling on the Earth. The reason is because of Newton's third law.
  13. If you play a baseball game on the moon, the force of the gravity of the moon pulling on the baseball will be less than the force of the gravity of the Earth pulling on the baseball when a baseball game is played on Earth. The reason is because the moon has less mass.
  14. On Earth, a feather falls slower than an extremely heavy object, because of air resistance.