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AL Physics Circular Motion
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Circular motion Revision Circular motion in horizontal Vertical circular motion Loop-the-loop
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Revision Newton’s Laws Circular motion in horizontal circles Centripetal force and acceleration Angular velocity, frequency & linear velocity
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Newton’s first Law A body continues in a state of rest or uniform motion in a straight line unless it is acted upon by external forces.
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No external force The body remains at rest. The body moves with a constant speed. Newton’s first Law
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The rate of change of momentum of a body is proportional to and in the same direction as the resultant force that acts on it. Newton’s second Law
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For fixed force A body with a larger mass moves with a smaller acceleration. A body with a smaller mass moves with a larger acceleration. Newton’s second Law
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For fixed mass A body with a smaller net force moves with a smaller acceleration. A body with a larger net force moves with a larger acceleration. Newton’s second Law
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If one body exerts a force on another, there is an equal and opposite force, called reaction, exerted on the first body. Newton’s third Law
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Body A exerts a force on body B, then body B exerts an equal and opposite force on body A. Newton’s third Law Body A Body B Force on B by AForce on A by B
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Newton’s third Law
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Circular Motion in horizontal circles
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Angular velocity = / t Linear velocity v = r Centripetal force F = m r 2 = m v 2 / r Centripetal acceleration a = r 2 = v 2 / r
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Circular Motion in horizontal circles Conical pendulum
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Do you remember what kind of forces provides the centripetal force to the bob ? Tension T Weight mg Centripetal force
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Vertical circular motion Bucket and water Does the water spill out the bucket when whirling ? If no, why doesn’t it spill out ?
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Vertical circular motion Bucket and water What kind of motion does the bucket perform ? Vertical circular motion What kind of force provides the centripetal force F c to the bucket ? Tension T Weight mg
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Vertical circular motion Bucket and water What kind of force provides the centripetal force F c to the bucket at the highest position ? F c = T + mg Tension T Weight mg
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Vertical circular motion Bucket and water What kind of force provides the centripetal force F c to the bucket at the lowest position ? F c = T - mg Tension TWeight mg
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Vertical circular motion Bucket and water What kind of force provides the centripetal force F c to the water at the highest position ? F c = R + W Reaction of the bucket R Weight of water W
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Vertical circular motion Bucket and water What kind of force provides the centripetal force F c to the bucket at the lowest position ? F c = R - W Reaction of the bucket R Weight of water W
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Vertical circular motion Loop-the-loop
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What kind of force provides the centripetal force F c to the mass ? The reaction of the track
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M.C. Exercise Class exercises Main menu True or False
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M.C. Question 1 Which of the following formula shows Newton’s second Law ? v = r = / t F = ma a = v 2 / r
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M.C. Question 2 At which position is the tension on the bucket largest ?
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True or False Question 1 True False If the angular velocity of the bucket at the top position is too small, water may spill out.
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TrueFalse In the Ocean Park, cart coast rider can loop the loop by tension. True or False Question 2
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You are wrong. Try again ! return Sorry ! Sorry !
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Correct ! Return
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