The Physics of Sliding on a Hill

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The Physics of Sliding on a Hill

• Min Woo Chung

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How to Ride The Sled

• Balance a rider is most stable if they sit like
  on the picture because Normal forces are always
  directed perpendicular to the surface and the
  gravity is always exist.

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Riding Sled on the Hill

• As shown in the diagram, there are always at
  least two forces acting upon any object that is
  positioned on an inclined plane which are the
  force of gravity and the normal force.

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Does the Sled related to Physics?

• The Sled is related to the physics because at
  point A, it has potential energy, between point A
  and B the point where speeds up, and point
  between B and C, it ends up with having kinetic
  energy.

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Kinetic Energy

• The Formula for Kinetic Energy is
• The bigger the mass the more kinetic energy an
  object has.
• Velocity is squared so kinetic energy is more
  dependent on velocity than it is on mass.

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Gravitational Potential Energy

• PE mgy
• Since PE is dependent on height, it is important
  to indicate the starting or reference point for
  the measurement.

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When the Sled has greater speed?

• The greater the hill of the surface, the faster
  the speed which the object will slide down. In
  physics, Objects are known to accelerate down
  inclined planes because of an unbalanced force.

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Newtons Second Law

• Newton's second law is the acceleration of an
  object is directly proportional to the net force
  acting on it and inversely proportional to its
  mass.

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If there is no friction, will the sled has same
speed?

• If there is no friction or air resistance, the
  sled would continue in motion with the same speed
  and in the same direction. Forces do not cause
  motion forces cause accelerations.

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Which position is the fastest?
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Data/Observation

• Leaning Forward The fastest
• Leaning Backward fast
• Sitting on the Slide The slowest
• According to the video, we could know which
  position is the fastest when we slide down on a
  hill.

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Conclusion

• As the experiment of sliding, Leaning forward was
  the fastest by putting the weight in front and
  having less air resistance.

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Example of sliding on the hill

• A boy is sliding down a hill that is 2.75m high
  and 5.43m long. If the coefficient of friction
  between the sled and the road is 0.33, what is
  the sleds speed at the bottom of the hill?
• Sol) PE Wf KE
• Mgy f?x 1/2mv(2)
• mgy un ?x 1/2mv(2)
• Mgy umg ?x 1/2mv(2)
• 10(2.75) (0.33105.43) 1/2v(2)
• 27.5 17.9 1/2v(2)
• 19.2 v(2)
• V 4.38m/s

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Bibliography

• http//www.physicsclassroom.com/mmedia/energy/hh.h
  tml
• http//www.physicsclassroom.com/Class/vectors/U3L3
  e.html
• http//www.sparknotes.com/testprep/books/sat2/phys
  ics/chapter10section5.rhtml
• http//www.glenbrook.k12.il.us/GBSSCI/PHYS/CLASS/n
  ewtlaws/u2l3a.html

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Thank You