Physics Cir cu lar   Mo tion
Circular   motion Revision Circular motion in horizontal  Vertical circular motion Loop-the-loop
Revision Newton’s Laws Circular motion in horizontal circles Centripetal force and acceleration Angular velocity, frequency & linear velocity
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.
No external force The body remains at rest. The body moves with a constant speed . Newton’s first Law
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
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
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
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
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 A Force on A by B
Newton’s third Law
Circular Motion in horizontal circles
Circular Motion in horizontal circles 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
Circular Motion in horizontal circles Conical pendulum
Circular Motion in horizontal circles Conical pendulum Do you remember what kind of forces provides the centripetal force to the bob ? Tension T   Weight mg   Centripetal force
Vertical circular motion  Bucket and water Does the water spill out the bucket when whirling ? If no, why doesn’t it spill out ?
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
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
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 T Weight mg
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
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
Vertical circular motion  Loop-the-loop
Vertical circular motion  Loop-the-loop What kind of force provides the centripetal force F c  to the mass ? The reaction of the track
Class exercises M.C. Exercise Main menu True or False
M.C. Question 1 Which of the following formula shows Newton’s second Law ? v = r     =    / t F = ma a = v 2  / r
M.C. Question 2 At which position is the tension on the bucket largest ?
True or False Question 1 If the angular velocity of the bucket  at the top position is too small,  water may spill out.  True False
In the Ocean Park , cart coast rider   can loop the loop by tension.   True or False Question 2 True False
You are wrong. Try again ! Sorry !   return
Congratulation ! Correct ! Return

Circular Motion

  • 1.
    Physics Cir cular Mo tion
  • 2.
    Circular motion Revision Circular motion in horizontal Vertical circular motion Loop-the-loop
  • 3.
    Revision Newton’s LawsCircular motion in horizontal circles Centripetal force and acceleration Angular velocity, frequency & linear velocity
  • 4.
    Newton’s first LawA body continues in a state of rest or uniform motion in a straight line unless it is acted upon by external forces.
  • 5.
    No external forceThe body remains at rest. The body moves with a constant speed . Newton’s first Law
  • 6.
    The rateof 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
  • 7.
    For fixed forceA 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
  • 8.
    For fixed massA 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
  • 9.
    If one bodyexerts a force on another, there is an equal and opposite force, called reaction, exerted on the first body. Newton’s third Law
  • 10.
    Body A exertsa 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 A Force on A by B
  • 11.
  • 12.
    Circular Motion inhorizontal circles
  • 13.
    Circular Motion inhorizontal circles 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
  • 14.
    Circular Motion inhorizontal circles Conical pendulum
  • 15.
    Circular Motion inhorizontal circles Conical pendulum Do you remember what kind of forces provides the centripetal force to the bob ? Tension T Weight mg Centripetal force
  • 16.
    Vertical circular motion Bucket and water Does the water spill out the bucket when whirling ? If no, why doesn’t it spill out ?
  • 17.
    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
  • 18.
    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
  • 19.
    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 T Weight mg
  • 20.
    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
  • 21.
    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
  • 22.
  • 23.
    Vertical circular motion Loop-the-loop What kind of force provides the centripetal force F c to the mass ? The reaction of the track
  • 24.
    Class exercises M.C.Exercise Main menu True or False
  • 25.
    M.C. Question 1Which of the following formula shows Newton’s second Law ? v = r   =  / t F = ma a = v 2 / r
  • 26.
    M.C. Question 2At which position is the tension on the bucket largest ?
  • 27.
    True or FalseQuestion 1 If the angular velocity of the bucket at the top position is too small, water may spill out. True False
  • 28.
    In the OceanPark , cart coast rider can loop the loop by tension. True or False Question 2 True False
  • 29.
    You are wrong.Try again ! Sorry !   return
  • 30.