Physics in Film

One of my absolute favorite superheroes is Batman.  I know technically, he’s not really a superhero…you know with the whole I’m just really good at martial arts, rich, charming debonair thing going on, but he’s still really super in my book.

So. Batman.

With its recent release, The Dark Knight is still quite vivid in my mind, so I’m going to concentrate on the glory exemplified in this thriller….

Let’s start with the end and the “high frequency pulse” that allows Mr. Fox and Bruce Wayne start playing around with.  I know, technically, the technology that Bruce uses isn’t the normal type of “superpower,” but his exploitation of the technology is what makes him super, so I’m going to go out on a limb here.  Mr. Fox says the “high frequency pulse” uses a kind of sonar to work, but sonar reflects sound waves on surfaces.  Cell phones emit electro-magnetic radiation, so its more logical that the high frequency would use radar instead of sonor.  Radar’s pretty cool and all, but for some reason the 3D level that Mr. Fox and Bruce elicit just doesn’t seem practical.

Moving on…

Batman loves to jump off the end of a skyscrapper, free fall, and then at the last possible second ignite his batwings to coast to safety!  What kind of force would that put on his arms?  The batwings aren’t much longer than his armspand, so pretty much his arms (attached to the wings) have to absorb most of the wind resistance in order for him not to have a face meet pavement moment.  That’s a lot of force…F=ma.  With all of that body armour, I’m sure Batman is no featherweight, and the acceleration due to gravity is 9.81 m/s^2.  Pretty intense.  The actual area of the wingspand itself would not hold his weight (like I said, they’re not much longer than his arms), so I’m doubtful that they would slow him down much at all, much less allow him to coast to safety/save the damsel in distress in the progress.

Batmobile vs. Joker’s Cargo Truck.

Okay.  Let me set the scene.  The Joker’s cargo truck (pretty big vehicular unit, if I do say so myself).  Batmobile coming at it straight on.  Hits cargo truck, lifts it on its 2 back wheels and pushes its backwards!  Goooooo Batmobile!

The batmobile is anyone’s dream car, but I’m doubtful that it could actually push a cargo truck (much heavier mass) backwards.  Just doesn’t seem to fit with the whole conservation of momentum gig.  Given, the batmobile can travel a lot faster, but the cargo truck has the mass element on its side.  I just don’t know that a car could take that kind of abuse, much less Batman (who is, unfortunately, still human).

So.  I know I’ve focused on Batman’s gadgets more than Batman himself, but his gadgets are what make him super.  And I had to pay homage to my Batman poster at home. 

Contact gets a lot of physics right, but has a lapse of probability at the end when it comes to the twin paradox at the very end of the film.  The film has reversed the roles of time dilation:  the time Ellie spends inside her “spaceship” should be less than the time than the people back at the space station.

How to fix it?

Let’s let Ellie through the wormhole.  She experiences what the movie says she experiences (pretty lights, pretty universe, hey dad, what’s happening!).  Back on Earth, everyone is eagerly awaiting her arrival back home.  Is she okay?  What is she seeing?  Is she ever going to come back?

After a few days, Ellie returns!  Hooray!  Instead of the emotional court where Ellie has to attempt to prove her trip, she instead relates what happened in space.  Many people still do not believe her (I like that her tape recorder stops working…I’m going to keep that part), but more people do.

As Wayne Campbell would say, Let’s do the super-happy ending!

Lets do the time warp again!

I can’t help thinking about the time warp and not referencing the dance from Rocky Horror Picture Show.

The time warp in Star Trek is a little bit different.  It is inexplicable for the plot.  How else would the crew of the USS Enterprise be able to rush back for their trial from the previous movie?  The ability to move so fast through space in needed for anyone of the Star Trek tales in order to keep the narrative moving, instead of spending real time (oh, I don’t know a couple thousand years), but its uses in Star Trek IV add a little bit more:  the ability to go back in time.  The ability to move forward in time in reference to a distant observer is realistic through Einstein’s Theory of Relativity, but the ability to go back in time is not.  It is illogical to travel faster than the speed of light.  The events in Star Trek are causally connected. Therefore, there is no way for the crew to be in the “present” (about to reach Earth), go back in time and spend a few days in the 1980′s, and then return back to the exact moment to fight off the “alien” (hahahaha) probe.

Nope.  Einstein won’t allow it.

Another interesting technology I found was the transporter.  Its vital for the crew to be able to steal the photons to revigorate the crystals for fuel, as it is to simply move around as they please on earth.

Side Note:  It’s probably a lot cheaper to film as well.  It’s easier to add a few nifty visual effects for the crew as opposed to allowing a working ramp to the ship for every single shot that they need to reboard.

I’m not quite sure how the transporter works with the Conservation of Mass and the Conservation of Energy.  Yes, the crewmates of the USS enterprise make it onto the ship in one piece, but how can the reaction that causes the bi-product of the light be explained?  The energy needed to move the crew from one place to the next would need to be great.  And obviously the bi-product to this reaction is the light.  But how can the light simply be created with no obvious effects to the crew members?

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I really did thoroughly enjoy this movie.

The power tug-of-war between General Grove and Dr. Oppenheimer was enthralling, and, what I believe to be, probably fairly realistic. I would have loved to see more of a focus on the scientists themselves, especially concerning the ethics associated with building such a powerful weapon. This project went from being an exciting problem to be worked out to reality entirely too quickly too me. Yes, the movie did show a few attempts at the scientists’ trying to slow down the project, such as the petition, but the movie focused more on the struggle involving General Grove and Dr. Oppenheimer more.

General Grove’s in a tight spot. He’s been assigned to make sure this weapon gets built on time, but the lax atmosphere necessary for the scientists to work together to solve the huge problem of nuclear weapons is against his nature. Insert clash with Dr. Oppenheimer. In the beginning, he is the voice of the scientists. He tries to cooperate with the general’s “Top Secret” rules while still allowing the scientists to be able to brainstorm creatively. Where is this voice near the end of the film? Instead of listening to the other scientists’ concerns about horrifying consequences staring them in the face, he simply shrugs it off. He is more concerned with being in control of such a historic project: He is “God” of the Manhattan Project. Everything takes second to this, especially his wife, mistress, and, most obviously, his fellow scientist. His collaborators’ guilt is insignificant next to the weapon itself, and what has been created.

I do believe the ethics did not get enough screen time. Just the idea of creating something that powerful is exciting, but the reality of such a destructive piece of equipment is probably even more frightening. I can only imagine the dissonance required to shrug off such a huge responsibility, especially after the bombs hit their mark. It would have been nice to see a little more development in this aspect of the film.

I loved the character Michael Merriman. He is such a Hollywood touch, but in this movie an effective one. His tragic role makes the movie even more lifelike. The lack of a happy ending for one of the lead characters makes the story even more believable. It also makes one think…if that happened to him being exposed so closely to radiation, the realization of how bad it really was in Japan is…mindblowing.

I give this movie a thumb up. Hollywood, you’ve done something right!

My father was in the Navy during the Cold War.  He is a decorated officer and was stationed on submarines during the cold war as an engineer.  My father is a smart man.  He has a few patents underneath his belt dealing with enginering on the submarines, and more recently (and completely different situation) his job at Michelin.  I have questioned him about his time working being in the Navy when I was growing up.  There is a lot he cannot tell me, simply because so much is still so top secret, even decades later.

He can describe the emotions though, specifically fear.

It was a time of uncertainty.  Nobody knew what the otherside knew, and the possibilities let imaginations run wild.  He was never specific, but he eluded to the possibility that his sub roamed the waters between Florida and Cuba.  During these periods of time, complete silence was expected by everyone on board.  Can you imagine days of walking on egg shells while in uncertain waters?

I know this seems somewhat tangent to the topic at hand, but my father’s stories, even with the holes in them, made me appreciate the power of nuclear physics.  Even before I studied the subject at all, I have had a deep respect for is importance and power, and my father’s stories made that respect.

I understand that nuclear power is useful.  It is relatively cheap and would give the United States the ability to become fairly independent of outside resources.  But at what cost?  Nuclear waste is definitely a problem.  I grew up in the upstate of South Carolina.  In other words, right next door to the Nuclear Waste Dumping Sight (aka Oconee).  Nuclear waste is harmful to the environment, and has the potential to be harmful to those that live nearwhere it is disposed.  Safety in general is an issue, but it is an issue in any circumstance.  Yes, the stakes are a little bit higher with dealing with something so dangerous, but if the right precautions are taken (as with anything else), the possibilities are endless when it comes the the mother load of power possible by using nuclear power.  In other words, the pros outweigh the cons, as long as the cons are not taken lightly.

Nuclear weapons, on the other hand, scare me.  The complete destruction that goes hand in hand with the “game” of nuclear warfare is simply horrifying.  It goes back to the old grade school game of King of the Hill:  my weapons are bigger than yours.  If they’re not, we’ll continue making bigger, more powerful, more destructive weapons.  This is not a good idea.  Human kind can not survive a full nuclear fall out.  Therefore, I do not believe even low yield devices should even be considered, simply because they won’t stay low yield for long.

What happened after the bow and arrow?  The musket.  After the musket? The cannon.  And so on and so furth.  With the implication of bombs, killing one person became killing many.  What happens after killing many?  Killing off an entire species?  The possibility is reality with nuclear warfare.

I hope a nuclear holocaust is not to happen during my lifetime, but it would be naive to say that the possibility isn’t staring us in the face.  You don’t hear to much about nuclear warfare or going nuclear at all in the mass, popular media, but that doesn’t mean that the research concerning bigger, better, more horrible possibilities has taken a standstill.

I’m no expert on “going nuclear.”  But the possibility of things getting really bad, really quickly could be staring us right in the face.

The physics in The Day After Tomorrow are extreme, but the movie does have a good point. What will happen if we refuse to look global warming in the face and accept the role its playing in climate change?

Public awareness for global warming has definitely increased over the last few years, but I don’t know how much The Day After Tomorrow has to do with this change.  The rate of climate change is so ludicrous in this movie that personally I took it as a joke.  People not schooled in the world of global warming would probably probably see it in the same light, and therefore not take the entire situation of global warming as seriously as it deserves.  Maybe if the movie was more realistic, it would have a bigger effect on people taking global warming seriously, but I suppose it wouldn’t make a very good movie because the reality is not as fast-paced and action packed as Hollywood normally likes.

Documentaries on the other hand would probably have a bigger effect on public opinion…if they were more easily accessible.  Most people simply do not watch documentaries.  This is a generation of people wanting to be entertained and many people feel that documentaries are simply not entertaining.

Most stories are based on truth, even if it is a very minute part of the whole picture.  The Day After Tomorrows lack of control of public opinion is sad.  Even though the physics is bad, the movie is still based on truth, and the dismissing of this truth could ruin the world for the next generation.

Sorry kids….my bad.

The Core.

Trying to name all of the bad physics in this movie is like trying to count all of the grains of sand on Folley…quite dubious if I do say so myself.  This is my attempt…

In the words of Julie Andrews…”Lets start at the very beginning”

The opening scene of the movie shows some business big shot falling dead for no apparent reason at the beginning of the movie.  We soon find out that he is not the only one! *gasp* Apparently 32 individuals in a 10 block radius have just dropped dead within seconds of each other.  The “solution”?  The Earth’s core has stopped spinning of course!  The electro-magnetic field collapsed!  We are all doomed!  I loved the thorough recognition of the scientific process to reach this conclusion (aka 5 seconds of Dr. Keyes thinking oh so hard).  It almost seems more or less impossible for nobody to have noticed such a huge event of the world.  I can almost understand nobody noticing the asteroid in Armageddon (okay only about 3% of space is actually monitered regularly), but hasn’t anyone ever heard of a compass?

How do you think compasses work?  Magnetism of the Earth of course!  So, just for humor’s sake, let’s assume everyone in the entire world decided that they would give their compasses the week off.  You know, those things work hard!  That leaves Dr. Keyes to save the day.  Go him.

Also, microwaves being deflected by a magnetic field?  Sorry, doesn’t work.  Magnetic fields just don’t do that.  So right there the entire premise of the movie is thrown out the window.  Even if the core could stop spinning (which I doubt), I don’t think we would be cooked by microwaves.  Just wouldn’t happen.  Cell phones use microwaves, and as far as I can tell, my phone hasn’t killed me yet nor caught me on fire.  So (jumping ahead a bit) I don’t see microwaves boiling oceans, breaking glass, melting bridges and tires.  Nope.  Don’t buy it.

I did like (well, not exactly like-i’m orinthrophobic) the scene where the birds go crazy.  Birds do use EM to maneuver, so to an extent, this is actually plausible.  I’m pretty sure a bird would not be flying at a velocity that could bust windows and windsheilds, but hey.  Well go with it, just for fun.

Onwards to the introduction of Maj. Rebecca Childs and the joys of space travel.  I’ve never been in space myself, but I’m pretty sure that space shuttles are simply not as nimble to come out of an orbit at that pace and angle.  Yeah, it looks pretty, but come on.  Well just assume (because I honestly have no idea about what equipment is used to navigate a shuttle, nor am I going to pretend) that the collapse of the electro-magnetic field interferes with the shuttle’s landing. Okay.  So how did it not crash?  I don’t buy the radical change in direction of the shuttle at that speed to land in that random strip of ground under all those bridges.  Space shuttles are big.  Really big.  Once again, I don’t believe them to be that nimble.  Especially not nimble enough to skid completely to the side just in time to stop right before the scaffold with the poor defenseless construction worker on it.

Go Hollywood.

All right.  Let’s get to the Virgil.

Oooo. Pretty ship.  Impossible ship, but pretty.  It’s made of unobtainium?  Not even touching that one.  Its too easy.  A material that can withstand those kinds of temperatures and pressures?  Okay.  Sure.  Yeah know, I might not be a genuis but I’m pretty certain that the core might be just a tad bit toasty (an estimated 3000-5000 degrees Celsuis) and with a pressure I can’t even fathom (it hurts my eyes to even try diving 15 feet).

Now what is this miraculous ship packing?  Equipment-wise?  An x-ray device that see through 3 feet of lead (okay….),  a communication system that works that deep for the majority of the journey to the core (okay…), and lasers that can cut through rock perfectly to form a “perfect” little circle!  I love it!  The equipment on its own is laughable.  Especially the amount of warheads they have to “restart” the core.  I don’t know much about weapons, but I just don’t think less then a dozen warheads would have that kind of power.  Sorry.  Not buying it.

All right.  Let’s acutally go on the journey!  Our story takes us to the Marianas Trench, where we find the Virgil positioned perfectly on a random platform ready for take off.  It’s released…and falls straight down.  Now that’s a big ship.  It must have been difficult to make an object that big to be perfectly weighted in order to do a perfect nosedive (I bet the Olympics would love a diver like that!).  Also, what about the characters reaction to the freefall?  Why are they struggling (in what appears to be pain) against their seatbelts?  They are in freefall.  They would have the feeling of being weightless.  Not my-eyeballs-are-about-to-pop-outta-my-head because of pressure.  Booooooo……

Meanwhile…back on the measly Earh’s crust…

Watch out for that lightning bolt!  Oh no!  Not Rome!  I don’t buy the number of lightning bolts per square meter and the amount of destruction they caused.  One lightning bolt blow up an entire stone statue?  A handful destroy the entire Coliseum?  The whole city left in fiery ruins?  That’s a lot of “sky-high altitude static discharge,” whatever that is.

Back to the Virgil.

Okay.  Trucking along through the Earth’s layers.  This is fun.

Oh no!  Look out for that giant…..diamond?  What?  What is an entire canyon of diamonds doing towards the Earth’s core?  And how can this unobtainium material be harmed by a diamond if its not crushed by the intense pressure or temperature that is easily gliding through?  It makes absolutely no sense.

Assuming the ship actually makes it to the inner core, once again, those few warheads would not have had the power to effectly getting the core moving again.  Seriously?

And what about getting home?  Not only can unobtainable withstand outrageaous temperature, pressure to die for (literally), but it can also convert heat into energy in order for the two remaining crew to make it back to the Earth’s surface?  What can this material not do! Besides of course be damaged by diamonds..oh yeah.

Even the ascent to the surface is unreasonable.  That far, that fast?  How would the human body withstand it?

Actually, how would the human body withstand this journey in general?  I wish I was cool enough to do that…

And that is all the bad physics I can possible think of.  I’m pretty sure I haven’t even touched half of it, but that just goes to show just. how. bad. The Core is.

So its obvious that the plan NASA comes up with will not save the world…at all…due to Conservation of Energy, but what would work?

I think our good man Newton and his Three Laws of Motion might be able to help.

Lets start with the First Law.  The asteriod is coming at the Earth at a constant velocity (25,000 mph or 1.1 * 10^4 m/s), and its going to stay this course, unless an external force acts on it.  So lets throw something really really big at it!  Remember the Futurama episode when the asteroid is coming at Earth, so the characters collect a ton of trash and “bounce” the asteroid away?  I’m thinking something along those lines, except not so….trashy.

Instead of having an asteroid the size of Texas, lets make it a little smaller.  Say 200 miles (3.22 * 10^5 m) as opposed to the 773 mi ( 1.244 * 10^6 m).  Lets also give NASA a little more time to evaluate the circumstances.  In the movie they have 2 weeks.  Lets go with more like 5 months (1.30 * 10^7 seconds). That makes the asteroid….

d=vt= (3.22 * 10^5 m/s) (1.30 * 10^7 seconds) = 4.186 * 10^12 m

away.

All right, so the asteroid is 3.22 * 10^5 m long, but whats the mass?  I’m going to assume that the shape of the asteroid is somewhat  cylinder-ish.  Therefore the volume of the asteroid would be…

V = (4/3) pi (d/2)^3

volume = 1.75 * 10^14 m^3

I’m also going to assume that the density of the asteroid(rock and metal) is 5500 kg/(m^3)

Therefore the mass of the asteroid is

mass = density * volume = 9.61* 10^17 kg.

We can work with that.

The average mass of a space shuttle is 2.03 * 10^6 kg.  Now something that size wouldn’t have a huge effect on an asteroid that big, but considering the distance away the asteroid is, and at a specific angle, I’m sure if an unmanned space shuttle is sent at a velocity equal to or greater than the space shuttle, then the asteroid’s course would be affected.  Hopefully this affect would send the asteroid great enough away from its course to Earth.

Therefore the world is saved and us Earthlings may live happily ever after.  For now.

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Conservation of Linear Momentum

Eraser is filled with even more fun physics to tear apart. I’m going to go with the opening classic rail gun scene (assuming that it is actually possible to have a handheld rail gun). The first scene that the gun is introduced has Lee’s former boyfriend being shot by the gun and completely thrown against the back wall. In order to disprove this possibility the conservation of momentum needs to be considered. Conservation of momentum states that the final momentum must equal the initial momentum.

Therefore:

p_final = p_initial

There are basically two collisions to consider in this scene. The first collision is between the bullet leaving the gun and the bad guy who’s shooting. In order to find out how much the gun (therefore the bad guy) recoil, it is necessary to know a few things first like the mass of the guy, the mass of the bullet, the initial velocity of the bad guy, and the both initial and final velocity of the bullet.

I’m going to assume that:

Mass of the bad guy is about 160 pounds, or about 73 kilograms

Initial velocity of bad guy is 0 m/s

Mass of the bullet is about .1 kg

Initial velocity of bullet is 0 m/s

Final velocity of bullet is about 150 mph or 67 m/s

Therefore:

P_initial = p_badguy + p_bullet

= m_badguyv_badguy + m_bulletv_bullet

= (73 kg) (0 m/s) + (.1 kg) (0 m/s)

= 0 kgm/s²

P_final = p_badguy + p_bullet

= m_badguyv_badguy + m_bulletv_bullet

= (73 kg) (v_badguy) + (.1 kg) ( 67 m/s)

P_initial = P_final

0 kgm/s² = (73 kg) (v_badguy) + 6.7 kgm/s²

v_badguy = – .09 m/s

The bad guy should have flown backwards at a speed of .09 m/s.

The Second Collision is in between the bullet and Lee’s boyfriend. Everything about the bullet in the first collision can be assumed to stay the same, except the final velocity will become 0 and the initial velocity will become 67m/s. Therefore we need to know:

Mass of Lee’s ex is about 180 lbs or about 82 kg

Initial Velocity of the ex is 0 m/s

Final Velocity of the ex is what we are going after

P_initial = p_ex + p_bullet

= m_exv_ex + m_bulletv_bullet

= (82 kg) (0 m/s) + (.1 kg) (67 m/s)

= 6.7 kgm/s²

P_final = p_ex + p_bullet

= m_exv_ex + m_bulletv_bullet

= (82 kg) v_ex + (.1 kg) (0 m/s)

So…

P_initial = P_final

6.7 kgm/s² = (82 kg) v_ex

v_ex = .08 m/s

Therefore Lee’s ex boyfriend should have flown back at a speed of about .08 m/s instead of at the speed that was portrayed in the movie.