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?
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.
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.
