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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
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