Download Roller Coaster Physics

Roller Coaster Physics
Energy and Work
Newton’s 1st Law
• An object in motion stays in motion in a
straight line, unless acted on by an
unbalanced force.
• In a roller coaster, the riders want to continue
moving in a straight line due to their inertia.
• The coaster track and car apply the unbalanced
forces to the riders, which makes it fun!
Roller Coasters and Gs
Roller Coasters and Energy
• Roller coaster cars have no motors.
• There usually is a large hill at the beginning of
the ride.
• As the cars travel up the hill, they gain energy.
• Potential Energy
▫ Energy of position
▫ Stored energy
Roller Coasters and Energy
• After the roller coaster reaches the top of the hill,
the force of gravity pulls it downward.
• As gravity accelerates the car, its velocity
increases.
• Kinetic Energy
▫ Energy of motion
Roller Coasters and Energy
Energy and Work
Energy is the ability to do WORK.
• Work is measured in a formula:
• Work = force x distance
•
W=F x d
• Where:
▫ Force, measured as Newtons (N)
▫ Distance, measured as meters (m)
▫ Work, measured as Newton x meter = Joule (J)
▫ So Joules (J) is the unit of measure for
both work and energy!
Work example problem:
• How much work is done when we push with
a force of 75 N to move a bookcase a distance
of 2 meters?
• Work = force x distance
• W = 75 N x 2 m
• W = 150 N x m
or
• W = 150 J
Potential Energy
• (Gravitational)Potential Energy Formula:
PE = weight x height
(remember: weight = mass x gravity)
• Where:
▫ PE = Potential Energy, measured in Joules (J)
▫ W = weight, measured in Newtons (N)
▫ h = height, measured in meters (m)
Potential Energy Example
A roller coaster car with a weight of 980 newtons
is pulled up a hill to a height of 40 meters. How
much potential energy did the car gain?
PE = w x h
PE = (980 N)(40 m)
PE = 39,200 J
Kinetic Energy
• Kinetic Energy Formula:
KE = ½ m x v2
This is the same as KE = mv2
2
▫ KE = Kinetic Energy, measured in Joules (J)
▫ m = mass, measured in kilograms (kg)
▫ v = velocity, measured in meters per second (m/s)
Kinetic Energy Example
At the bottom of a hill, a roller coaster car with a
mass of 100 kg is traveling with a velocity of 28
m/s. What is the kinetic energy of the car?
KE = ½ m v2
KE = ½ (100 kg) (28 m/s)2
KE = ½ (100 kg) (784 m2/s2)
KE = 39,200 J
Law of Conservation of Energy
• Energy is not created or destroyed, it only
changes forms.
Roller coaster examples:
• Energy from a motor is used to pull the cars uphill. That
energy is converted to potential energy.
• As the cars travel downhill and speed up, potential
energy is changed into kinetic energy.
• During the ride, the tracks heat up due to rolling friction.
Kinetic energy is changed into heat energy.
Energy and Work
• Energy is the ability to do work.
• Work is applying a force over a distance.
• Formula for Work:
W=Fxd
Where:
• W = Work, measured in Joules (J)
• F = Force, measured in Newtons (N)
• d = distance, measured in meters (m)
Roller Coaster Physics