Transcript Catapults, Concussions and Cars

Catapults, Concussions and Cars
(and Coasters!)
“I feel the need for speed!”
- Maverick, Top Gun physics class
Take a guess…
• Rank from greatest acceleration to smallest
acceleration
a)
b)
c)
d)
e)
aircraft launched from carrier
Car drag racing at Raceway Park
your skull/brain during concussion
Kingda-Ka accelerating at beginning of ride
Parachutist in freefall, before chute deploys
Now guess actual numbers……
What really happens on a carrier??
• http://www.youtube.com/watch?v=VPdBiHfXYk&feature=related (USN documentary, give data, start part
1 at 8:00, end part 2 at 4:20)
• http://www.youtube.com/watch?v=IQ-Iv9Js-1I (French)
Physics for fun and profit!!
Remember your guess?
Let’s watch …..can we get
good data to confirm it?
http://www.youtube.com/watch?v=ZSzOd__feI
w&NR=1 (bus, for fun)
http://www.youtube.com/watch?v=6eoYJEGHLp
o (jet dragsters, some data?)
Shortcut to drag racing vinny budano vs moran.lnk
Physics hurts my brain!
• There’s more than one type of concussion..
– http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1
55415/
– Typical acceleration rates
• If 1 g = acceleration due to gravity
• Then 1 g = ~10 m/s2
• Concussion = 100’s of g’s
– i.e. ~ 1000 m/s2
Kingda Ka-a-a-a-a-a-a-a-hhhh!
– Tallest and fastest in the world???
– What launch speed in what time???
– Calculate the acceleration
Designers can’t let the
riders pass out or get
concussions !
You calculate the acceleration!
• Calculate the acceleration of the cars using the
distances and times from the videos….
• Are you close to your guess?
• How does this compare to being launched off
an aircraft carrier? To freefall? To concussion?
Can you design an aircraft carrier?
Consider the F-18
• Aircraft Performance
– Why is speed at takeoff important?
– What speed does your airplane require for takeoff?
Goal: design a reasonably sized carrier,
equipped with reasonably powered
catapults and arresting gear…
How much ‘real estate’ do you need?
• Use the limited, yet powerful, knowledge you
have to determine the length of the runway
required….
• What are the design restrictions?
• What data do you know?
• What data do you need to know?
• What equations do you have? Refer to the
notes in your handout
Great success!!
• Your calculated length of runway should be
close to the actual length of 200 - 300 feet!
What about the steam catapult?
How much power is enough?
Do we have enough info or knowledge to
determine that?
Can you design a catapult that would give a pilot
a concussion on takeoff or landing?
• Suppose a small child rolls off a bed that is 0.37 m above
the floor.
• If the floor is hardwood, the child's head is brought to rest
in approximately 1.8 mm.
• If the floor is carpeted, this stopping distance is increased
to about 1.0 cm.
• Calculate the magnitude and duration of the acceleration in
both cases, to determine the risk of injury.
• Assume that the child remains horizontal during the fall to
the floor. Note that a more complicated fall could result in a
head velocity greater or less than the speed you calculate.
• a.Hardwood Floor
• b.Carpet Floor
More phun physics
• http://www.youtube.com/watch?v=Fh7fQz4xz
W4&feature=related (bus race)
• http://thedailyreview.com/news/local-racecar-driver-who-appears-on-espn2-talks-aboutracing-1.885237 (info on drag racing fuel, etc)
Physical limitations associated with
accelerations
• How much can the human body take?
• Homework……
Are you faster than a speeding bullet?
• Try this…….
– You have to choose a reasonable distance through
which you can accelerate the whole time!
– Have someone time you for three trials at that
distance
– Calculate your acceleration using the distance and
the average time
Is your calculated acceleration reasonable?
How do you match up to Usain Bolt?