Welcome to bownet Home of the Bow School District

					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        Inertia
your seat on a loop?

What force powers        Gravity
Roller coasters?
Why do you experience
                             Inertia
crushing feelings?

        Where?     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
                      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
    Compare  coasters?
       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
            The friction with the
            water and the blunt
             shape of the car
            makes the wave so
  I love    huge and beautiful!
 physics
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 =

				
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posted:3/24/2011
language:English
pages:23