Download What force powers Roller coasters? Why do you experience free fall?

Hold on to your hats, guys and gals, this is one fast trip!
What makes a roller coaster so
fun?
Some think it is the free fall
Others the speed and acceleration
Maybe it’s the fear you feel
when the roller coaster
Sloooowly climbs that first hill!
Roller Coasters
What keeps you in
your seat on a loop?
Inertia
What force powers
Roller coasters?
Gravity
Why do you experience
crushing feelings?
Inertia
At the bottom of a hill as the
train starts to go up
Why do you experience free fall?
Inertia
Where? At the top of a hill as the
train starts to go down
Where?
Energy
Mechanical Energy
1. Potential Energy
2. Kinetic Energy
Thermal Energy
1. Friction
Looping Coaster at Canobie
PE = mgh
Why is this hill lower?
How can we calculate the energy lost to friction?
KE = ½ mv2
Spiral Twists
Why have
these loops?
Acceleration = change in velocity over time
Velocity = speed and direction
Water Rides—are they roller
coasters?
Compare
Both have hills
Both use gravity
Both have energy transformations
Contrast
Water powers the ride—not gravity alone
Water is also the friction to slow down—not brakes
No track
PE to KE transformation not as key as water speed
The Boston Tea Party
I love
physics
The friction with the
water and the blunt
shape of the car
makes the wave so
huge and beautiful!
Circular Rides—A huge variety
This type of ride makes many people
Feel ill. How?
What do the forces look like on a
swing ride?
And in a circular pattern with
constantly changing direction
Direction of the ride
Riders move out from the center
This is different from a ride with a track,
because there no track/seat to push back.
What is the reaction force then?
But they all work the same way
What other force is at work
here?
Hint: it pulls you down
If you are going on the ride with Hagrid (a giant),
should you or he sit on the outside?
Hint: Which way are you being pulled or pushed?
Let’s Look at the Forces
Centripetal force
Direction of ride
The direction is constantly changing which means
The acceleration is constant
Is this one different?
Do you really need the restraints?
If someone were to say, upchuck, what direction
Would the substance go?
Eww—GROSS!!!
Circular Motion
(One complete cycle)
Circular Motion
Circular Motion
Pirate Ship—Pendulum Rides
FREE FALL
What is the thrill of this ride?
What produces that thrill?
Inertia
Free
Body
Diagram
Inertia keeps the body going up
When the ship is going back down
The force of friction goes against
The direction of motion
Direction of movement
Force of Weight
How Could We Calculate the
Amount of Energy “Lost” Due to
Friction?
Where we release the “ship”
PE = mgh
Where the highest point is
after an amount of time
PE = mgh
If we find both PEs and subtract. . . h – h. . .we have it!
Now, what if we want to find the average
PE lost on each swing?
Pendulum Physics
• Figure 13.4: The Simple Pendulum
Force the rider feels is
defined by:
Fr = - (m)(g)(sin )
Pendulum Physics
• One Period (T):
l = length of string
g = 9.8 m/s/s
Pendulum Physics
• The frequency of oscillation is the inverse
of the period:
• frequency =