Hold on to your hats, guys and gals, this is one fast trip!

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 coasterSloooowly climbs that first hill!

Roller CoastersWhat keeps you in your seat on a loop?

What force powers Roller coasters?

Why do you experience free fall?

Why do you experience crushing feelings?

Where?

Where?

Inertia

Inertia

Gravity

Inertia

At the top of a hill as the train starts to go down

At the bottom of a hill as the train starts to go up

EnergyMechanical Energy

1. Potential Energy2. Kinetic Energy

Thermal Energy

1. Friction

Looping Coaster at CanobiePE = 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 hillsBoth use gravityBoth have energy transformations

ContrastWater powers the ride—not gravity aloneWater is also the friction to slow down—not brakesNo trackPE 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 huge and beautiful!I love

physics

Teacher’s pet

Circular Rides—A huge varietyThis type of ride makes many people

Feel ill. How?

What do the forces look like on a swing ride?

Direction of the ride

Riders move out from the center

And in a circular pattern with constantly changing direction

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

If you are going on the ride with Hagrid (a giant), should you or he sit on the outside?

What other force is at work here?Hint: it pulls you down

Hint: Which way are you being pulled or pushed?

Let’s Look at the ForcesCentripetal force

Direction of ride

C

The direction is constantly changing which means

The acceleration is constant

How does inertia figure into this?

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

What is the thrill of this ride? What produces that thrill?

FREE FALL

Inertia

Free Body Diagram

Direction of movement

Force of Weight

The force of friction goes againstThe direction of motion

Inertia keeps the body going upWhen the ship is going back down

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 stringg = 9.8 m/s/s

Pendulum Physics

• The frequency of oscillation is the inverse of the period:

• frequency =