2001: A Space Odyssey is a film about a series of encounters between humans and mysterious, yet advanced machines built by an unknown alien species that are affecting human evolution. The characters in the film go on a space voyage to Jupiter tracing a signal emitted by one of these machines. You would expect the physics in this movie to be good considering it’s a “science” movie and you’re not wrong. However there are some areas where you can find bad physics. In general, the film does a good job of respecting the laws of physics. In this review, we’ll look at good and bad examples from some scenes that happen on the spacecraft during the voyage.

Good Physics:

When the stewardess is walking with the “grip shoes” up the circular wall and then on the ceiling. This scene is scientifically accurate because; since there is no gravity, there is no sense of direction. This means that being “upside down” is irrelevant due to the fact that there is no difference between upside down and right side up in space. The stewardess would feel completely normal either way. As for the “grip shoes”, there is no scientific reason why they couldn’t work. They would allow her to stay planted in the surface. Although there is no normal force or artificially gravity, the grip shoes keep her from floating off the surface every time she pushes off to take a step.

When the astronaut is jogging around the giant circular section of the spacecraft, it is an example of good physics because of centripetal force. He does not need “grip shoes” here because this section of the spacecraft is actually spinning to create the illusion of gravity. In reality, its not gravity that he’s feeling, it’s an inward force that the floor exerts on the man as a result of the craft spinning in a uniform circle. Just like in the other scene with the woman and the “grip shoes”, since there is no real gravity, there is no sense of direction. So “upside down” does not technically exist. Wherever that man is in that section of the spacecraft, as long as he was touching the floor, he would feel normal thanks to the artificial gravity

In one of the camera shots of the spacecraft cruising through space, we see that the engines are off. This is scientifically accurate because the ship wouldn’t need to have its engines on to maintain speed. There is no friction or air resistance in space so the ship can technically coast to its destination once it has reached a desired speed. Many movies with space ships always show the ship with the engines always running (probably because it looks cool to have blue flames coming out of the back of the spacecraft). But in reality, all that would do is cause the craft to accelerate indefinitely, making for a rather unsafe trip.  

The last scene I will analyze is my favorite for two reasons. This is the scene when the person comes out of the pod and into the spacecraft. There is good physics in this scene because before he closes the hatch, there is no sound. This is scientifically accurate because there is no medium for the sound to travel through, which explains the dead silence. This is a concept that many moviemakers are not aware of; or more likely, tend to ignore; especially when depicting explosions in outer space.

Bad Physics:

Unfortunately, the last scene I mentioned in the good physics section also has some of the worst physics in the movie (in my opinion). One of the reasons this part is bad is because the man holds his breath while floating in the airless, pressure less section of the craft. In reality, he would explode rather spectacularly because the pressure inside of his body is much greater than the pressure outside his body.

Another scene with bad physics goes back in the scene with the rocket engines being off. If you noticed, the light is hitting the spacecraft from the left. However the right side of the craft is still pretty well lit. In reality, the side with no light source would completely pitch black because in space, there is nothing for light to reflect off of. So only the areas in direct contact with light would be lit up.

Despite the major problem in the escape pod scene, and the minor problem with the lighting, this film does a very good job of obeying the laws of physics. 

Hancock Analysis

Intro: This week, I chose to analyze Hancock’s super powers. Hancock is played by actor Will smith and appears in only one movie; “Hancock”. His powers include flying, super strength and bullet resistance. In the movie, there are numerous scenes with obvious physical flaws for a variety of reasons; of which I chose five in particular to analyze. See attached pictures for individual calculations.  

Problem 1: A runaway group of gang members is driving down the LA freeway in a Cadillac Escalade. Hancock flies into the back of the car and attempts to negotiate with the bandits. When they do not comply, he stomps his feet through the floor, planting them into the road surface and bringing the SUV to a stop in 4.5 seconds. During the skid, the SUV travels 4.5 Escalade car lengths, which is equivalent to 25.2 meters. The car weighs 2732kg with all four people in it (three bandits and Hancock). My goal was to find the force that Hancock had to exert on the ground opposite the direction of motion to bring the car to a stop in that period of time. I also wanted to find force felt on the mortal passengers over that period of time. After working out the calculations, I determined that he would have to exert a force of 21,710.3N over 4.5 seconds on the road. I also figured out that each passenger (not including Hancock) would experience about 124.5lbs of force on their bodies over that same time period.

Part two of this problem is after he stops the car, he picks it up and flies to some undetermined altitude. After some more negotiations, he still isn’t satisfied so he drops the car. He lets the car go in free fall for 5 seconds before catching it and bringing it to a stop in roughly half a second. The car is traveling 49 meters per second before being brought to a stop, and the passengers feel a force of 1542lbs when it does stop.

Problem 2: One of the worst physics problems in the movie is when Hancock stops a freight train dead in its tracks (pun intended), without even budging. The train goes from traveling 20 meters per second to 0 meters per second in an estimated 1-second. The movie actually does a decent job of portraying what would happen to the train because we can see the cars piling up and de-railing themselves behind the stopped locomotive as a result of conservation of momentum. Assuming Hancock was capable of stopping a 10 million pound train, there would have to have been an astronomically high coefficient of static friction between his shoes and the ground, otherwise despite his strength, he would slide backwards after being hit with the train. To calculate the coefficient of static friction, we have to know a few things about the scene first. We can estimate the train weighs about 10 million pounds because that’s the weight of an average half-mile long freight train. The train was going roughly 45 mph (20.11 meters per second). And finally we know Hancock weighs 100kg. We know the sum of the net forces equals mass times acceleration, and since Hancock doesn’t move when the train hits him, his acceleration is zero. So after rearranging the equation, we see that the force of the train equals the force of friction. The force of friction equals mew times the force of the normal, which is mass, times gravity. So we plug in the numbers we know and solve for mew (which is the coefficient of static friction). After doing the calculations, we find that the coefficient of friction will have to have been at least 93,078.6 which is unbelievably high (and as far as we are concerned, impossible). To put it in perspective, the coefficient of static friction of Velcro is 6.

Problem 3: Quite often in the movie, as Hancock is walking down the street, he takes off flying by jumping off the ground. In one particular scene, he jumps straight up and reaches the coulds in 1.5 seconds. Based on the type of clouds shown in the movie, we can assume he flies upwards of 10,000 feet before punching into the could layer. I wanted to calculate the force he exerts on the ground when he jumps that high in that amount of time. To do this, we have to know the mass of Hancock, the distance he traveled and the amount of time he did it in, all of which we have. Assuming that he applies the force to the ground almost instantly, we can represent that as 0.01 seconds. After doing the calculations, he shows that Hancock would have to apply a force of 40,000,000N to the ground to achieve that result.  

Problem 4: In a flashback, Hancock is shown throwing a beached Grey Whale back into the ocean. The only question in this scene is whether or not the whale would survive the Impulse of the throw by Hancock. To find out, we first have to calculate the impulse. We know the mass of the whale is 36287kg or roughly 80,000 lbs. However that’s all we know besides that we can estimate that the DT of the impulse is about half a second. However we can figure out the final velocity of the throw by determining how far the whale went. The whale is in the air for 5.5 seconds. We know initial velocity in the y-axis is the same as the final velocity in the y axis, and assuming the whale traveled in a parabolic motion, you can divide the DT by 2 and do a free fall problem from that. The reason we can do this is because at the top of the arc, the velocity in the y is zero so the only force acting on it is gravity and the initial velocity is zero and we can divide the time by 2 and know that it falls for 2.75 seconds before hitting the water. Once we have that value (22.05 meters per second as the final velocity before it hits the water), we can use trig to find the velocity in the x-axis. To use trig, we need the launch angle of the whale which can be estimated at 15 degrees after watching the clip several times. Once we know the velocities in the x and y axis, we use the Pythagorean theorem to find the overall initial velocity (40.25 meters per second). Finally, we use that in the impulse equation and find that Hancock exerted a force of 2921103N to the whale. And I’m not marine biologist but I don’t think whales are designed to withstand that kind of force.

Problem 5: In this final problem, Hancock is in a standoff with a gunman in a convenience store. He grabs a candy bar and challenges the gunman to a draw; his candy bar vs the gunman’s bullet. We see Hancock throw the candy bar with such force that it strikes the gunman and sends him flying backwards through the store window and onto the street. The goal here is to calculate the velocity of the candy bar and find the force on the gunman after he is hit with it. We can estimate that he flies backwards roughly 25 feet in 1.5 seconds. Figuring the mass of the gunman is about 70kg, which means the candy bar would have to be traveling at least 9567.4 meters per second. That happens to be 28 times the speed of sound. When the candy bar hits the gunman, it applies a force of 8,132.4N over an estimated time period of 0.05 seconds. 

This week we watched Armageddon, which is a fantastic film despite the horribly inaccurate physics portrayed in the movie. NASA’s plan for saving the earth was flawed in several ways. If we ignore the fact that people could actually land a shuttle on the surface of an asteroid and then drill down into it and plant a nuclear weapon, then there is still one huge remaining flaw. Given the size of the asteroid, one nuclear weapon would not even come close to doing what it is shown to do in the movie. Even the largest nuclear weapon ever thought of (not even successfully built) would only split the asteroid and move each piece a few hundred meters in either direction before both smash into the surface of the earth.

My new plan is based off NASA’s plan from the movie, but with a few changes. I would still send astronauts up to the asteroid but instead they would drop 5 Tsar bombs and blow up the asteroid 4 hours after it passed the moon. Then I would send a second and third team, each to land on the surface of the individual pieces of asteroid, and on the surface, detonate more bombs after another 4 hours, causing the pieces to accelerate in the y-axis and allow them to cover enough distance in the y-axis in the remaining 2 hours of time before they smash into the earth.

In doing the calculations to figure out how much explosive power would be needed to propel each half fast enough to clear the earth in the remaining 2 hours, I realized the amount of force needed would be light-years beyond anything mankind is capable of generating with the technology we have today. I determined it would take the equivalent of 5.18x10^11 megatons of TNT, per piece. That would be more than 5.18 Billion Tsar bombs per half of asteroid.

Eraser Movie Scene

            This week we watched “Eraser” which in my opinion, suffered in comparison to Mission Impossible III. Eraser failed across the board in cinematic categories such as acting, screenwriting, and of course, accurate portrayal of scientific principles; more specifically, physics. In one of the last scenes of the movie; an epic battle with futuristic weapons takes place on the docs of the Baltimore Harbor. Arnold Schwarzenegger, also known as “The Eraser” is seen firing two weapons that shoot a projectile “close” to the speed of light. For a moment let’s suspend our disbelief that any such weapon would even exist and just focus on the physics.

            The problem that we are investigating is, if the henchmen that Schwarzenegger shoots go flying backwards, shouldn’t he too go flying backwards from the recoil of the gun?

            Since we know the projectile is traveling “close” to the speed of light, we can estimate that as being 3.0x10^7 meters per second. Since they don’t tell us how much the aluminum rounds weigh, I estimated it as 1 gram, or 0.001 kilograms per round. Beyond that, the only things we have to know for the problem are the weight of Schwarzenegger and the weight of the henchmen. After a quick Internet search, I found out that Arnold was roughly 115 kilograms in the movie, and I estimate that the average henchmen is around 65 kilograms. Knowing all of this, we can use conservation of momentum to find out what really should have happened in that scene.

            After performing the calculations, I found that if Schwarzenegger actually fired both rail guns at the exact same time, he would have been launched backwards at a velocity of over 413.8 meters per second. In addition, the henchmen that were shot would have been launched backwards at a rate of 461.5 meters per second. That kind of acceleration would be fatal for anyone, even the Eraser proving that physics is clearly not a required course for anyone intending to major in film related studies.