# PHYSICS OF by yurtgc548

VIEWS: 3 PAGES: 15

• pg 1
```									PHYSICS OF ROLLERCOASTERS

Nathaniel McClain II
PHY 3091
Florida State University
PHYSICS OF ROLLERCOASTERS

• Allen, John (b. May 21,
U.S.--d. Aug. 17, 1979,
designer of roller coasters
who ignited the coaster
boom of the 1970s
following the mid-century
decline in amusement
parks.
PHYSICS OF ROLLERCOASTERS
POTENTIAL ENERGY
• Stored energy that depends            • Potential energy is a property of a
upon the relative position of             system and not of an individual body
or particle. It depends only on its
various parts of a system. A              initial and final configurations; it is
train of cars on a gravity-               independent of the path the object
powered roller coaster has                travels. The value of potential energy
more potential energy raised              is arbitrary and relative to the choice
of reference point. Gravitational
above the ground at the top of            potential energy near the Earth's
a hill than it has after falling to       surface may be computed by
the earth along the hill's                multiplying the weight of an object by
inclined track. In the elevated           its distance above the reference point.
position it is capable of doing       •   Potential energy may be converted
into energy of motion, called kinetic
more work. By extension, the              energy. Traditionally potential energy
higher the lift hill, the greater         is included with kinetic energy as a
the potential energy.                     form of mechanical energy so that the
total energy in gravitational systems
can be calculated as a constant.
PHYSICS OF ROLLERCOASTERS
POTENTIAL ENERGY

• AT THIS POINT IN THE RIDE .
. . at the top of the lift hill, the
potential energy of the
gravity-powered coaster is at
its greatest, because the
coaster is at its highest
elevation. Beyond this point,
as gravitation gives the car
velocity, the potential energy
is transferred into kinetic
energy. The coaster does,
however, regain some
potential energy each time it
climbs another hill or ramp on
the rest of the ride.
PHYSICS OF ROLLERCOASTERS
GRAVITY
• In mechanics, the universal force
of attraction that affects all
matter. It is the weakest of the
four basic physical forces, but, on
the scale of everyday objects near
the Earth, it is the dominant one.
The fall of bodies released from a
height to the surface of the Earth
and the weight of resting bodies
at or near the surface are the
most familiar manifestations of
gravitation. Gravity is the
roller coasters, accelerating the
cars through all the twists and
turns of the ride, from the lift hill
through to the brake run.
PHYSICS OF ROLLERCOASTERS
VELOCITY
• Quantity that designates how fast and         •   Roller coaster rides incur many changes in
in what direction a point is moving.            speed and direction, or velocity, and the
Because it has direction as well as             rate of this change is acceleration. It is not
true, as often thought, that the speed of a
magnitude, velocity is known as a               car at the bottom of a hill is equal to its
vector quantity and cannot be                   initial velocity plus its drop velocity; actually
specified completely by a number, as            the greater the drop height, the less initial
can be done with time or length, which          velocity influences final velocity. Along the
are scalar quantities.                          same lines, speed is not directly proportional
to the drop height but to the square root of
•   A point always moves in a direction             the drop height. Doubling the speed of a
that is tangent to its path; for a              coaster ride requires quadrupling the height
circular path, for example, its direction       of the hill.
at any instant is perpendicular to a line   •   AT THIS POINT IN THE RIDE . . . the track
from the point to the center of the             curves back upward and the speed drops as
circle (a radius). The magnitude of the         the roller coaster climbs the second hill.
velocity (i.e., the speed) is the time          Owing to the change in velocity, the riders
rate at which the point is moving along         experience upward centripetal
its path.                                       acceleration in the form of positive g-
forces. This compression makes them feel
heavier than normal. On the climb the
coaster regains some potential energy
that it had lost to kinetic energy on the
previous descent.
PHYSICS OF ROLLERCOASTERS
ACCELERATION
• Time rate at which a velocity is
changing. Because velocity has both
magnitude and direction, it is called a
vector quantity; acceleration is also a
vector quantity and must account for
changes in both the magnitude and
direction of a velocity.
•   If the velocity of a roller coaster
moving on a straight path is increasing
(i.e., if the speed, which is the
magnitude of the velocity, is
increasing), the acceleration vector will
have the same direction as the velocity
vector. If the velocity is decreasing
(that is, the coaster is decelerating),
the acceleration vector will point in the
opposite direction. So, whether the
coaster is increasing speed down a hill
or decreasing speed up a hill, it is
regarded as acceleration in the
mathematical sense.
PHYSICS OF ROLLERCOASTERS
ACCELERATION
• Changes in acceleration greatly contribute to the thrill of
a roller coaster ride. A rider may feel greater sensations
in a low-speed coaster with sharp acceleration changes
than on a faster coaster with a smoother ride. Pure
speed is often not as recognizable as the surge of
acceleration during a coaster ride.
• A common fallacy is that acceleration increases along
with the weight of the riders and the car, when actually
the acceleration of a coaster in free-fall is independent
of its mass. Acceleration does increase, however, with a
steeper angle of descent.
PHYSICS OF ROLLERCOASTERS
ACCELERATION
• AT THIS POINT IN THE RIDE .
. . at the bottom of the second
hill, the coaster, in theory,
reaches an instant of zero
acceleration, at the point
where its speed is greatest,
relative to anywhere else on
that hill. Zero acceleration also
occurs for an instant at the top
of a hill, where in turn the
speed is at its lowest level. At
the bottom of the dip, the
riders experience compression,
or acceleration stress,
owing to forces greater than
their usual weight.
PHYSICS OF ROLLERCOASTERS
FRICTION
• Force that resists the sliding or rolling of one
solid object over another. Frictional forces, such
as the traction needed to walk without slipping,
may be beneficial; but they also present a great
measure of opposition to motion. Friction, along
with air resistance, or wind drag, are dissipative
forces that are neglected in idealized discussions
of fundamental mechanics, in which gravitation
is the only force considered.
PHYSICS OF ROLLERCOASTERS
PHYSICS OF ROLLERCOASTERS
ACCELERATION STRESS
• Physiological changes
that occur in the human
body in motion as a result
of rapid increase of
speed. Rapid acceleration
and surges in
acceleration are felt more
shifts.
PHYSICS OF ROLLERCOASTERS
CENTRIFUGAL FORCE
• Quantity, peculiar to a
particle moving on a
circular path, that has the
same magnitude and
dimensions as the force
that keeps the particle on
its circular path (the
centripetal force) but
points in the opposite
direction.
PHYSICS OF ROLLERCOASTERS
KINETIC ENERGY
• Form of energy that an object or a particle has
by reason of its motion. If work, which transfers
energy, is done on a roller coaster by applying a
net force, such as gravity, the coaster speeds up
and thereby gains kinetic energy. Kinetic energy
is a property of a moving object and depends
not only on its motion but also on its mass. The
kind of motion may be translation (or motion
along a path from one place to another),
rotation about an axis, vibration, or any
combination of these.

```
To top