Sunday, October 6, 2019

Understanding Movie Physics: Avengers: Infinity War

Avengers: Infinity War. The beginning of the end of Marvel's Infinity Saga. It is an amazing movie that immortalizes some of Stan Lee's famous comic book characters. Filled with action packed fight scenes between humanities greatest heroes and aliens, such as Thanos and his Black Order,  who seek destroy half of all life in the universe, Infinity War tests many forms of physics, but in this blog we are specifically going to look at scenes that defy Newton's Laws of Motion.

Scene 1: Doctor Strange and Levitation

One of the simpler defiances lies in the power of levitation or unaided flight. Many characters like Iron Man or Star Lord have rocket propelled forms of flight, meaning there is a force keeping aloft, however, for characters like Doctor Strange, they have no force keeping them in the air. According to Newton's Second Law, gravity acting on a living being with mass (which Doctor Strange definitely has)  while in the air means he should be falling downwards. Since Doctor Strange does not
have a downward facing force to keep him in the air, he should be falling to the ground but since that is not portrayed in the movie, this counts as a violation.

Scene 2: When He Should Have Gone For The Head.....

In this scene, Thanos has just killed Vision and inserted the Mind Stone into the Infinity Gauntlet. In an attempt to prevent the Snap, Thor flings Stormbreaker into Thanos' chest but fails to kill him. It instead gravely wounded him, but not enough to prevent Thanos from killing off half of all life in the universe.

The problem with this scence is that when Thor hit Thanos with Stormbreaker, it should have created a crater or indent in the earth of some sort but it didn't. This violates Newton's Third Law of Motion. The downward force created by Stormbreaker is enough to create a crater as evidenced by a previous scene where Thor slams down is hammer and creates one. The same thing should have happened with Thanos. The force from the impact would cause an opposite upward reaction from the ground around the impact point which leads to the formation of the crater. Even though in this scene Stormbreaker hit Thanos and not the ground, the force would have channeled through him and still have the same effect.

Scene 3: The Hulk in the Hulk Buster

(Sorry this one is a link! It was the only way to get this scene in!)

In this scene, Bruce Banner has been equipped with the Hulk Buster armor, a huge metal suit designed to defeat the Hulk in violent confrontation. He is running across a grassy field towards the front lines of the battle that is about to commence. But again, the physics in this scene is screwed. Much like the previous scene, this one is a violation of Newton's Third Law. It is violated by the non-existence of an impact craters. The Hulk Buster armor is a giant heavy metal contraption that is exerting a good amount of force on the ground beneath him as he his running, but no crater (aka the opposite reaction) is created which in fact should be present.

Sunday, September 22, 2019

Understanding Movie Physics: Armageddon

Armageddon. The end of the world. Humanity's execution by meteor. That is what would have happened in the movie if Bruce Willis' character, Harry Stamper, and his team had not drilled a hole in the meteor, threw a nuke inside it, and blew it up. To be brutally honest however, that plan would have ultimately failed and humanity would have perished...even NASA has confirmed that the nuke idea used in movie would fail. Luckily enough, in reality, NASA has contingency plans in place that actually will protect the Earth from asteroids. 

Last year, the White House Office of Science and Technology released a plan called the "National Near-Earth Object Preparedness Strategy and Action Plan". The document describes 5 goals NASA is going to take over the next decade to deal with any asteroid threat. None of which requiring a drilling team - or even an a regular astronaut for that matter- to go into space and forgo the threat.

It will be to much to go into the specifics of the specifics of the objectives that are laid out in the 18 paged plan, but it will be good to provide a basic overview:

  • Objective 1: Improve Surveying Methods and Technology 
    • In a sense, find areas to improve existing survey telescopes and provide those using them with new training to make them proficient in the use of the new technology in order to upgrade NASA's process of detecting, tracking, and analyzing asteroids that may pose a threat to the Earth. These improvements will help "reduce current levels of uncertainty and aid in more accurate modeling and more effective decision-making," as described by the document.

Image result for asteroid survey telescopes
  • Objective 2: Estimation of Probability Improvement
    • After improving the tracking and basic analyzing of an asteroids, NASA wants to work on upgrading the process of putting all that information together to get the most accurate prediction possible of when and where on the Earth a possible asteroid could impact the Earth. With this information, more "emergency-handling" qualified agencies like the Federal Emergency Management Agency (FEMA) can come up with the best way to approach the situation when dealing with an incoming asteroid.
  • Objective 3: Deflection Ideas

    • Once as much possible information and estimations have been made, NASA is tasked inventing new technologies and methods that will help remove the threat of an incoming asteroid, primarily by moving it out of the way. One such method is the idea of a Near-Earth Reconnaissance mission in which a satellite or spacecraft would move in the direction of the oncoming object and in some way move it out of line with the Earth and neutralize the threat (this is where the new technologies I mentioned before will be needed).
    • NASA plans on testing its Double Asteroid Redirection Test (DART) in 2022 when it encounters the asteroid Didymos in 2022. The plan for this is to launch the DART probe in 2021 and by some time 2022 have the probe crash in the asteroid at 21,600 mph and study the effects and determine how much force is needed to move an asteroid that could potentially hit Earth out of its orbit.
  • Objective  4: Improve International Teamwork
    • This goal aims to reach a high enough global cooperation under the guidance of the United States in order to properly prepare the rest of the world of an asteroid strike and the aftermath of one should deflection attempts fail.
    • To help achieve this goal, NASA's Planetary Defense Coordination Office is constantly in talks with the United Nations in order to decide what a global response to an asteroid strike should look like. 
  • Objective 5: The Job of the United States
    • The final objective tasks the US government and all its appropriate agencies with developing a plan in the event of an actual, potentially devastating asteroid threat and a plan for a possible aftermath as well.
    • NASA's job would mainly be enacting NEO impact plans in hopes of deflecting the asteroid and FEMA would work to notify anyone who would be threatened by the asteroid and would send out emergency responders to help with a recovery process if its needed.

Wednesday, September 18, 2019

Understanding Movie Physics: Eraser

Arnold Schwarzenegger. Action scenes. Rail guns. Inaccurate physics. All of these factors contribute to the thrill that is the movie Eraser. However, it's that last factor, inaccurate physics, that tends to bug many of this movie's viewers. Especially the physics that violate the law of the conservation of momentum.

The scene posted below, like many of the other's seen throughout of the movie, show a human, often either Arnold's character or one of the enemy thugs, firing a weapon called a rail gun. In the movie, a rail gun is explained to be a gun that uses electromagnetic energy to fire a lightweight aluminum bullet at almost the speed of light, and it is here that we discover the inaccuracy of these scenes.

Eraser Scene: 

Whenever one of the speeding rounds hits a human body, that individual is most often sent flying across whatever environment they are in , but the shooter is always left unaffected and in the same position as they were before. This is the violation of the law of  conservation of moment as previously mentioned, which states "In the absence of external forces interacting upon an object or a system of objects, the total momentum will not change". This basically states that the momentum before and after the collision must be the same. Therefore the shooter must face a negative 
recoil velocity that sends them flying backwards that is equivalent to the positive velocity of the bullet being shot forward in order for the momentum's of each object to cancel each other out and get a total momentum value of zero that was present before the collision. Another approach is that neither the shooter or the one shot face any kind of momentum that would send them flying and instead don't get sent flying like before.

Due to the complete disregard of the law of conservation of momentum, I am rating this movie with an RP (retch physics) rating.

Wednesday, August 28, 2019

Understanding Movie Physics: Mission Impossible 3

by Anthony Forcella

Mission Impossible III seems to be the focus of many when it comes to those who crave action scenes with guns and explosions, chase scenes through maze-like cities, and stunts that seem impossible to the average man. While many of these scenes are appealing to the eye, the physics behind them are questionable. At some points the film tries to apply math and physics to some of the stunts presented, but for us, the ones in search of the truth, are not satisfied with those explanations and will analyze them ourselves to test the actual possibilities.

Scene 1: The Building Swing in Shanghai

This scene is perhaps the most famous (or infamous to movie physics critics) of the action stunts portrayed in the movie. Prior to the actual scene, Tom Cruise's character, Ethan Hunt, proposes the idea to swing from a point on a neighboring that is higher than the one he has to break into and makes some measurements in order to try and validate the physics behind the idea. So, as our job as movie physics analysts, we test the actual reliability of these measurement and the scene of the jump itself, and to do that a question about it must be formed. The most obvious of which being:

Can Hunt actually make the full distance of the swing?

Referenced from the planning scene from the movie, the taller building (Point A) is measured to be 226 meters high and the smaller (Point B) to be 162 meters in height. The distance between Points A and B was measured to be 47.55 meters. He starts off with a sprint which we can estimate to be about 9 m/s (Initial velocity) before he jumps off the edge of the first building. It takes him about 25 seconds to complete the stunt before separating himself from the jump cord and since the jump is occurring in mid-air we have to calculate how fast gravity is pulling him down and decelerating him which we can assume is -9.8 m/s^2.

Scene 2: The Leap at the Bridge Battle

In this scene, Hunt has just been attacked by a group of enemy forces and speeding drone. The attack results in major damages to the bridge they are on and the loss of their captured enemy, Solomon Lane. In an attempt to recapture Solomon, Hunt gives chase to the enemy on foot and eventually finds himself cut off from them with the edge of the bridge being on his left, and giant pile of rubble to his right, and a gaping hole out in front of him. In order to get to Solomon, he leaps across the gap and barely manages to make it across. The question here to ask is: 

Can Hunt make the leap across the gap?

To begin with, we are going to need to estimate the speed at which Hunt is running to be about 9 m/s and he seems to be pushing himself off at an angle of 45 degrees. We also need to determine the length of the gap (distance Hunt needs to travel) in order to determine if the velocity of Hunt and the angle of his jump is sufficient enough to cross the gap. By analyzing the leap itself, we can see that the gap measures about 5 leg-lengths across. Since we cannot determine the actual length of Tom Cruise's leg, we have to use the average length of a human leg which is about 75 cm which we go on to multiply by 5 to get a total length/distance that Hunt has to jump being 375 cm or 3.75 meters. We also need to calculate the total amount of time that Hunt takes to cross the gap which we can assume by watching the scene and considering the effect of slow motion that it takes Hunt about 2 seconds to cross the gap.  And again we also need to include the effect of deceleration that gravity has on Hunt which we can assume is -9.8m/s^2.

Scene 3: Repelling at the Vatican

In an attempt to capture Solomon Lane, Ethan Hunt has to sneak his way into the Vatican. Amidst his variety of costumes and false personas is a scene where Hunt repels down from a wall and suddenly stops inches from the ground. The question we will ask here is:

At what velocity did Hunt repel down the wall?

Before he begins to repel down, he measures the total height from his position on top of the wall  to the ground to be 16.55 meters with a small electronic device. Hunt goes on to fall off the edge without any initial velocity (Vi) so we can assume that it can measured as 0 m/s, and the same can be said of his final velocity as he comes to a complete stop (Vf = 0 m/s). Since Hunt is letting gravity control the acceleration and not having any other outside force propel him we can use the acceleration due to gravity on Earth (9.8 m/s^2 ) as his acceleration. Once Hunt comes to a stop, he reaches down to the ground to steady himself. The average length of a human are is about 0.635 meters, but given that his arms are bent at about half lenght we are going to assume that he is about 0.3175 m off the group at the time of his complete stop.