Physics in Film: Stephen Chadbourne

Scene: Ship running aground

   Question: Given the time that elapses, how far should the ship have traveled after it initially hits the dock (it seems to be crashing for eternity, yet it travels less than the distance of the ship)?

   Relevant Data: Length of ship (which is the approximate distance it travels after hitting the dock), initial speed at collision, and time it takes to stop.

   Approximate Values: One of the crew states that the ship is traveling at 10 knots shortly after hitting the dock. It takes 3 minutes and 12 seconds to come to a complete stop after traveling between 250 and 300 meters, which allows us to calculate the rate of deceleration.

Scene: Cruise ship collides with small vessel causing an instantaneous explosion

   Question: Is the collision of a cruise ship and a sail boat likely to cause a fireball explosion?

   Relevant Data: Quantity and type of gasoline on the small vessel, materials on the bow of the cruise ship, materials aboard the sail boat, location of the gasoline aboard the ship, a bunch of thermodynamics values I’m not familiar with in the least.

   Approximate Values: The boat appeared to be no longer than 35 ft, and a quick search on Google revealed that similar boats use diesel fuel with a capacity around 40 gallons.  The hull of the sail boat is likely fiberglass, though wood and metals are likely also used in the boats construction.  The cruise ship’s bow is probably reinforced with steel.  As for the explosion itself, I’m not sure I could venture a guess; perhaps the temperature at which point diesel fuel explodes, it’s energy given the quantity, I really don’t know.

Scene: Alex is yanked from the boat by the sea plane and dragged through the water.

   Question: Is it physically possible to hold on to a cable as you are dragged through the water by a plane?

   Relevant Data: Weight of Alex, speed of plane, speed of boat just before Alex is yanked off, force at which point a limb will dislocate or break, and amount of chop in the water.

   Approximate Values: Alex is probably roughly 180 pounds and would probably not skid through the water nicely, meaning lots of drag.  The speed of the boat is unlikely to exceed 50 mph.  I’m no expert, but based on a quick search on Google, the smallest planes take off at about 70 mph, and therefor the plane must be going at least slightly slower.  If this is the case, Alex accelerates 20 mph in about a second.  I don’t know how best to measure chop, but it appears that the waves were no larger than 12 inches, though being in the wake of the plane would likely diminish waves.  The average barefoot skier, which starts out much like how this scene unfolds (on your back and then over to your stomach), travels at about 35 mph.  I can tell you from experience that it’s extremely hard to hold on at even 20-25 mph, and 35 mph is next to impossible for me.  It would seem laying on your stomach traveling close to 70 mph would be out of reach.  I can’t even approximate how much force it would take to dislocate one’s shoulder, but I think it’s safe to say a lot less has caused serious injury, and if nothing else his fingers probably wouldn’t be able to hold on.

I am testing this out / didn’t feel like having this blank.