Uniform Circular Motion

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Uniform Circular Motion
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UCM

• Uniform circular motion can be described as the
  motion of an object in a circle at a constant
  speed.

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• An object moving in a circle is accelerating.
• The direction of the acceleration is inwards.

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Question

• An object is moving in a clockwise direction
  around a circle at constant speed. Use your
  understanding of the concepts of velocity and
  acceleration to answer the next four questions.
  Use the diagram shown at the right.

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• Which vector below represents the direction of
  the velocity vector when the object is located at
  point B on the circle?

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• Which vector below represents the direction of
  the acceleration vector when the object is
  located at point C on the circle?

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• Which vector below represents the direction of
  the velocity vector when the object is located at
  point C on the circle?

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• Which vector below represents the direction of
  the acceleration vector when the object is
  located at point A on the circle?

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Imagine that you are a passenger in a car which
is making a right-hand turn
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Centripetal force

• Any object moving in a circle (or along a
  circular path) experiences a centripetal force

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Out on a date

• Rex Things and Doris Locked are out on a date.
  Rex makes a rapid right-hand turn. Doris begins
  sliding across the vinyl seat (which Rex had
  waxed and polished beforehand) and collides with
  Rex. To break the awkwardness of the situation,
  Rex and Doris begin discussing the physics of the
  motion which was just experienced.

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What a great date..

• Rex suggests that objects which move in a circle
  experience an outward force. Thus, as the turn
  was made, Doris experienced an outward force
  which pushed her towards Rex.

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Things really start to heat up..

• Doris disagrees, arguing that objects which move
  in a circle experience an inward force. In this
  case, according to Doris, Rex traveled in a
  circle due to the force of his door pushing him
  inward. Doris did not travel in a circle since
  their was no force pushing her inward she merely
  continued in a straight line until she collided
  with Rex.

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What do you think?

• Who is correct?

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The Forbidden F-Word

• Does the sensation of being thrown outward from
  the center of a circle mean that there was
  definitely an outward force?

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Roller Coasters and Amusement Park Physics
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Clothoid loops
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Where Does the Net Force Always Point?
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Feelings of weightlessness and heaviness are
associated with the normal force
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Superman, The Ride of Steel!
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