Carousel Physics

Physics H 1WJune 2007

Outline

• Conscious Commuting• Carousel History• Questions and

Calculations• Horizontal Accelerometer• Summary Sheet• Reflection

Conscious Commuting

0 to 20mph in 12 seconds

Convert 20mph to m/s:

20mph . 0.44m/s = 8.8m/s

1 mph

Find the acceleration:

8.8m/s – 0m/s = 0.733m/s2

12s – 0s

Force on me when the bus begins to move:

95lb . kg = 42.27kg 2.2lb

(42.27kg)(0.733m/s2) = 30.99N

My weight in Newtons: (42.27kg)(9.8m/s2) = 414.25N

Conscious Commuting

When the bus starts up do you feel thrown forward or backward?When the bus begins to accelerate you feel thrown backward because the bus is pulling us forward.

When the bus is traveling at a constant speed do you feel as if you are moving?You do not feel like you are moving because the bus is traveling at a constant speed, the bus isn’t accelerating or decelerating.

If you eyes are closed, how can you tell when the bus goes around a corner?You can tell because you fall to one side or the other when the bus goes around a corner.

What is a Carousel?

• It’s an amusement ride made of a rotating platform with seats for the passengers

• The seats are typically horses, but can include dogs, cats, rabbits, pigs, deer…

• Animals often move mechanically up and down to simulate galloping

• Music is often looped while the ride spins

Origins of the word “Carousel”

• Originates from the Spanish word “carosella” which means “little war”

• In the 1100’s Turkish and Arabian horsemen used carousels as an exercise to prepare for combat and as a game.

• It was used to train men in cavalry because it prepared and strengthened the riders for combat.

“Flying Horses”

• Early carousels didn’t have platforms, just the animals hanging from poles and chains

• The animals would fly out from the centripetal force when the device began to spin

• The carousels were either pulled by walking animals, people pulling ropes, or cranking

Platform

• The platform carousel was developed in the mid 1800’s

• The animals were attached to the wooden floor which was suspended in the air from a centerpole

• Theses devices were steam-powered

1909 Illions Carousel

Speed 4 Revolutions/Minute

Diameter 7.75 Meters

Circumference of the outer ring of the

horses50 Meters

Angle banking of the floor

-4°

Manufacturer M.C. Illions

Direction of travel Clockwise

Questions and Calculations

Where would you need to sit if you wanted to experience the greatest speed?

You would want to sit on the outside because all the horses complete the circle in the same amount of time. The horses on the outside have to travel more distance in the same amount of time, which gives them a faster linear speed. Linear velocity is different between the two rows of horses while the angular velocity is the same between all the horses.

If you were on a horse and were to drop a coin while the ride was in motion, where would it land relative to you?

It would land behind you because of centripetal force.

Questions and Calculations

Find the frequency in Hertz:

4 rev . min = 0.0667Hz min 60sFind linear

velocity50m – 0m = 3.33m/s 15s – 0s

Find centripetal acceleration:

aR = v2 = (3.33m/s)2 = 2.86m/s2

r 3.875m

Horizontal Accelerometer

Vertical Direction:T = mg/cosØHorizontal Direction:T = mg/sinØ

Turn onto 95: 15°

90° - 15° = 75°

mg tanØ = maa = g tanØ

a = (9.8m/s2)tan(75) = 36.57

Summary

Kinetic energy is being converted into gravitational potential energy:Scream, they carry you up to the top, which uses kinetic energy. When you’re at the top you have gravitational potential energy. PEgrav = mgy

Name the ride that fits the description

The translational (linear) accelerations is negative:Mind Eraser, at the end of the ride you come to an abrupt stop. v2 – v1 = a t2 – t1

The centripetal acceleration is significant:Nightwing, because the ride spins in a circle really fast to make you feel like you are flying. aR = v2

r

Reflection

• Had a good time• Bus didn’t break down• Stay at the park later• Buy the flash passes• Lunch buffet