Jack Sparrow's velocity when he falls down the ravine?

[cyrusn]

Homework Statement

What is Jack Sparrow's velocity when he falls down the ravine in Dead Man's Chest?

Homework Equations

P=MV?

The Attempt at a Solution

I don't know where to start. I think this is a projectile problem because he is in freefall when he falls down the ravine right? Or maybe it is a momentum problem because he falls through and breaks a few bridges on his way down.

 

[Doc Al]

To treat this as a physics problem, you'll have to provide more details.

 

[phinds]

What is Jack Sparrow's velocity when he falls down the ravine in Dead Man's Chest?

That's exactly like asking "how high is up?"

Where did the problem come from? Book? Hand-out sheet? Your notes?

 

[cyrusn]

That's exactly like asking "how high is up?"

Where did the problem come from? Book? Hand-out sheet? Your notes?

Our assignment was to analyze movie physics. My group chose Pirates of the Caribbean Dead Man's Chest. In the movie Jack Sparrow falls down a ravine when he is escaping from the tribe (you can find the clip here: )

 

[haruspex]

this is a projectile problem because he is in freefall when he falls down the ravine right? Or maybe it is a momentum problem because he falls through and breaks a few bridges on his way down.

Then it may be both, but at what point is the speed to be determined?

 

[phinds]

you can find the clip here:

Which is utterly useless in terms of giving any kind of numerical answer to your question. This is getting to be just silly. Do you understand why I say that?

 

[Bystander]

movie [insert]imaginary[/insert] physics

 

[Navin]

Well this is fun.Now we have 2 choices
A)look at this from a purely physical point of view and consider it impossible
B) make lotta inaccurate assumptions and get a somewhat believable answer
Lot of people chose A but that's no fun

Now it should be noted my maths and intuition are horrible so I leave the calculations up to you.

Well first try to find the velocity leave aside the the momentum...I don't think it would matter much(considering how inaccurate our assumptions are going to be)

Assume the hieght of the ravine...I dunno...100 metres ?(since this is disp in negative direction ,-100)
Acceleration due to grav is constant at -9.8m/s^2(I'm assuming the downward direction as negative )
And so on...

Yea this isn't helpful...uh...yea,...
(And our narrator wonders how he shall pass his physics test in a few weeks)

 

[Navin]

Iooked at that clip again...no he'd be dead if it were 100m...I don't know make up a nice believable number.
His initial velocity is zero.Lets assume it from the point the trick gets stuck.Thats our starting point.The bridges don't affect his velocity so to hell with that.(OK fine theoreticaly it has a minute effect...but come on...I ain't Dyson or some dang to be able to call that !).We know his Displacement...I don't know -30m?...time is...well approx 49-35= 14 sec(calc from video)

Therefore using

V^2 - U^2 = 2aS where S is disp

V^2=2. -9.8 . -30
V= the root of +24.249m/s...
It should be noted what I did is extremely inaccurate and stoopid.so stupid that u need stoopid to describe what I did...but I dunno...some answer is better than no answer ?Anyway in the end -JACK SPAROW SHOULD FRIGGIN DIE AFTER THAT FALL...but hey Hez Sparrow

 

[Phantoful]

Please use the question format that the site tells you to use, it will help you in the end.

I'm guessing you are a high school student, so I would suggest ignoring the bridges, because it becomes a topic of civil engineering.

Assuming that you would want to find terminal velocity and without friction (very unrealistic) you would need to guess the height of the ravine... You then have v_o, a, and d. What equation will you use to find v_f ?

As for finding out if Sparrow survives the fall, I can tell you that the maximum atmospheric pressure a human has ever survived at is 33 atmospheres, or about 3343.7kPa. Make of that what you want. (Pressure = Force / Area if you're not familiar)

Iooked at that clip again...no he'd be dead if it were 100m...

Interestingly, the highest height a human has survived from falling without a parachute or any special equipment is 10,160 meters. So you can't really just rule out 100 meters. From a quick google search, heights of ravines are usually around 3,900 ft.

 

[haruspex]

I would suggest ignoring the bridges,

Since a video clip is available, it should be possible to measure the time and depth of each fall stage. That would be the best way of finding the velocity at the beginning and end of each. That allows the impulse of each collision to be found.
The unknown part is the peak force involved. If we pretend the force is constant during an impulse then we can measure the duration of each and estimate it from that.

 

[Navin]

Phantofol my physics teacher would love to replace me with you in his class ! Good input