Monday, October 7, 2019

Newton's Law's in Motion

Avengers: Infinity War is a fun and exciting action movie that takes place in a universe with many super powered heroes and villains fighting it out in battles of phenomenal scale. What the lack in realistic physics and proper application of physical laws, they make up for with cool visuals and ridiculous feats. I would give Infinity War a NR for its obvious ties to comic book physics and ignorance of actual physics. 

Newton's 1st Law
Sir Isaac Newton's first law of motion states that an object in motion will continue in that motion forever until acted upon by an outside force. A perfect example of this principle being ignored in Infinity War comes right at the beginning of the film. When Thanos destroys the ship with all the Asgardians on board there is quite a large explosion. With an explosion of that magnitude debris (like Thor who was inside the ship when it exploded) would be hurled away from the spot of the explosion at a non zero velocity. When the Guardians find Thor though, he is just floating around where the ship was with no real noticeable velocity. By looking at the motion of objects in the background and comparing it to Thor it seems that the perceived motion of Thor is coming from the motion of the Guardian's ship, and not from Thor. In reality, the debris that was flung into space, like Thor, should be a ways away from the spot of the explosion because it would not have any outside forces stopping its motion so it should travel in a straight line away from the wreck at the speed the explosion set it at. 
Newton's 2nd Law 
Newton's second law of motion states that if there is an acceleration of on object with mass, then there must be a force applied to it to cause the acceleration. The biggest disregard for this law in the film is how Ebony Maw and Doctor Strange just levitate in the air without any sort of thrust upward. For them to float they would need to supply a force greater than and in the opposite direction to their gravitation force to lift themselves off the ground and then a force equal to their weight while in the air. Neither of these magicians supply any sort of visible force to allow them to float in mid-air but the movie just looks past that and allows them to do it anyway.
Newton's 3rd Law
Newton's third law of motion states that every force exerts a force with equal magnitude but in the opposite direction to the original force. One moment where this seemed to be ignored in Infinity War is when Thanos pulls one of Titan's moons and throws it at Iron Man. While the movie shows Thanos pulling and exerting a force to pull the moon downward, there is not indication of Thanos having an equal and opposite force acting against him. If there was an equal and opposite force, he would either be flung from the surface of Titan or if he was anchored enough, Titan would shift toward the moon. 



Sunday, September 22, 2019

Armageddon Destroyer: The Kinetic Impactor

In the movie Armageddon, a huge asteroid is heading toward Earth which would end all life as we know it. NASA's only solution is to send the best oil drilling team in the world to drill into the huge rock and blow it up from the inside. While this may sound like a far fetched science fiction scenario, NASA has been looking into solutions if this same situation actually happened.

NASA's solution to an asteroid collision with Earth is known as the Kinetic Impactor Mission. As the name implies, it intends to use the object's momentum against it. The plan would be to send an object at the asteroid with enough speed to deflect it out away from Earth. The impactor would hit the asteroid off center to try and guide the object past Earth.

According to the National Academy of Sciences, the Kinetic Impactor Mission would require a significant amount of time as a warning before the asteroid hit to prepare the impactor. If the asteroid is a smaller asteroid, it is estimated that we would need 1-2 years notice to design, build, and launch the impactor with enough time to guide the asteroid away. For larger asteroids though, it is estimated that it could require a 20 year warning to be able to safely protect Earth.


Eraser

The film "Eraser" details the story of a Witness protection agent named John Kruger, player by Arnold Schwarzenegger, who fakes the death of the people he is assigned to protect and gives them fake identities to keep them safe from those who are trying to harm them. This is how he earned to nickname "the Eraser." After he learns about the illegal arms sale of handheld rail guns, he does everything he can to stop take down the sale and find who is responsible.


In the scene above, Kruger picks up the rail guns that were supposed to be sold to a terrorist organization and used it against them. While Arnold holding two rail guns firing them at the same time is a cool scene and an awesome action piece, one has to wonder, "Could Arnold Schwarzenegger even hold and fire those guns?"

In the film they say that the rail gun fires projectiles "the speed of light", which in it self is impossible due to the theory of general relativity. Assuming that the projectiles could move at a velocity equal to the speed of light and that the projectiles have an equal mass to the standard 5.56 bullet (62 grams), we could calculate the momentum at which the bullet has and how that momentum affects the shooter (Arnold Schwarzenegger). The momentum of the bullet should be the same magnitude but opposite direction of Kruger's momentum.

mv = rail gun
mv = Kruger

mv = mv
(.062 kg)(3 * 10^8 m/s) = 114 kg * v
1.86 * 10^7 kgm/s = 114 kg * v
v = 163,158 m/s

As shown in the equation above, after firing the rail gun, John Kruger should fly backwards at a velocity of over 160,000 m/s which is over 14 times faster than the escape velocity of earth.

In conclusion, not only would it be physically impossible for a hand held battery to produce enough energy to accelerate an object to the speed of light, but firing such rail gun that could would destroy anything that tried to fire it, and Kruger was shooting two at the same time. Due to these facts I give Eraser an NR rating. There is a blatant disregard for physical principles and concepts with the rail guns in the movie.

Sunday, September 1, 2019

Mission Impossible III

In the film Mission Impossible III, Ethan Hunt (played by Tom Cruise) seeks vengeance for his pupil by taking out Owen Davian but ends up uncovering a bigger threat to global security in the process.

Scene 1: Shanghai Rope Swing
In the film Ethan Hunt swings between two buildings using a rope to gain access to the roof of a lower building. After the rope had let out all of its length it becomes taut and violently jerks his body. The main question going through many viewers minds after this scene is could he even survive that much force. There are only three main measurements needed to make to see if he could survive the jump.
Gravitational acceleration: 9.80 meter per square second or 32 ft per square second
His weight: 67 kg or 148 lbs
Time of fall: >10 seconds (beginning of jump scene is in slow motion so it is hard to pin down the exact time of the fall)
What amount of force a human body can withstand: about 5g's before passing out (>70 to kill a person)

Scene 2: Bridge Jump
After the drone blows up a chunk of a bridge, Ethan Hunt has to run and jump over a the gap that formed but could he physically do it? To figure this out one would need to know:
His sprint speed: >28 mph or  > 11 m/s
Angle at which he jumped: >30 degrees (estimate off of re-watching the clip)
Length of the gap: ~15 ft or ~5 meters

Scene 3: Building Base Jump
In an escape effort Ethan base jumps from a building and ends up pulling his parachute late so would he be able to survive the fall? To find this one would need to know:
The minimum height to safely pull a parachute: 2000 ft or 610 meters
How height Ethan was when he starts falling the second time: ~20 stories or 200 ft or 61 meter

Overall I give this film a rating of RP