Transcript The Physics of Sliding on a mountain

The Physics of Sliding on
a Hill
Min Woo Chung
How to Ride The Sled
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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.
Riding Sled on the Hill
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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.
Does the Sled related to Physics?
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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.
Kinetic Energy
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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.
Gravitational Potential Energy
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PE = mgy
Since PE is dependent
on height, it is
important to indicate
the starting or
reference point for the
measurement.
When the Sled has greater speed?
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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.
Newton’s Second Law
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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.
If there is no friction, will the sled
has same speed?
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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.
Which position is the fastest?
Data/Observation
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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.
Conclusion
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As the experiment of
sliding, Leaning forward
was the fastest by
putting the weight in
front and having less air
resistance.
Example of sliding on the hill
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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 sled’s 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) – (0.33*10*5.43) = 1/2v^(2)
27.5 – 17.9 = 1/2v^(2)
19.2 = v^(2)
V = 4.38m/s
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Bibliography
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http://www.physicsclassroom.com/mmedia/e
nergy/hh.html
http://www.physicsclassroom.com/Class/vect
ors/U3L3e.html
http://www.sparknotes.com/testprep/books/s
at2/physics/chapter10section5.rhtml
http://www.glenbrook.k12.il.us/GBSSCI/PHYS
/CLASS/newtlaws/u2l3a.html
Thank You