Analyzing Physics in Video Games: Tension Force and Realism

ah sorry man i gotta link up with harvey's group good morning

today our goal is to investigate the video we just saw we're going to learn a little bit about

video game analysis and ultimately we'll be answering the question

if the tension force that the character experienced isn't realistic

so how do we analyze physics in video games notice the area i've circled it says 100

meters these markers or waypoints in video games are useful to measure distance

it's telling us that the character is about 100 meters below the top of the structure

now what if there is no marker or waypoint in a video game can you still analyze it well the answer

is yes you can however it gets a bit more challenging you'll need a ruler

and you ultimately need to use a scale to analyze the video game but it can still be done

so the next question is how do we determine the tension force to do this we'll need to estimate the

acceleration and ultimately we'll need a measurement of distance and time

and so here's our first frame of interest at this point notice the cable is tight

so there is tension in the cable 15 frames later batman has moved to this position

so what does 15 frames later really mean so notice i've circled our initial time point

where batman is 99 meters below the structure with the video paused on a computer you

can do the following you can use the period key to move the video one frame forward

at a time so what did i do i pressed the period key 15 times until i arrive to the image that i

circled there where the character is 87 meters below the structure

if you want to move the video one frame backward at a time then instead of using the period key you

would use the comma key so in conclusion if you want to move a video one frame forward or one frame

backward what you need to do is either use the period key or the comma key

when the video is paused in youtube so now that we know how to move forward and backward

via frames in a video on youtube the real question though is 15 frames represents how much time

well to understand this we need to know the fps of a video fps stands for frames per second

for this specific video game it was 30 frames per second and so

if we've moved the video 15 frames forward and the video records at 30 frames per

second we divide and we end up with a time of half a second

so that's really important in terms of analyzing video games understanding how to get a time

next how far has the character moved well circling those markers notice he started off at 99 meters but

he ends up at 87 meters in half a second so in total he's moved 12 meters so we know our distance or our

displacement is 12 meters initially the character is at rest we're going to assume constant

acceleration now for my further analysis of this video game it seems to be constant

acceleration but this is an assumption at the end of the day so be aware of that

using this classic kinematic formula we're going to determine acceleration substituting our numbers and working

through some math we end up with an acceleration of 96 meters per second squared

let's determine the force of tension here's another assumption notice that the cable

is at a slight angle however we'll draw tension straight upwards

it turns out that that angle will affect the measurement of tension but it's too hard to measure in the

video game because we don't have another perspective so we'll assume that the character is

heading straight upwards instead of at an angle notice that the vector associated

tension is drawn much longer than the weight or the force of gravity that's because we know the character has

an acceleration upwards and so we'll define the positive direction as pointing up

and the negative direction is pointing down writing our net force statement its

tension subtract weight or force of gravity substituting the equation we know that f

net equals mass multiplied by acceleration we also know that the weight or the force of gravity

is equal to mass times the acceleration due to gravity question is what is the character's mass

well i googled this and i looked this up on the internet it seems to be around 90 kilograms but

this again is another estimation i want you to pause the video right now and solve for the tension force

all right i hope you've completed that substituting and rearranging we end up with a tension

force of 9522 newtons insignificant digits at best probably two sig figs

because we really don't know his mass all that well nine thousand five hundred newtons

so is this nine thousand five hundred newtons realistic reviewing some sources on the

internet typical grip strength seems to be somewhere between 400

to 700 newtons for a person so after all of our assumptions even if we're off by a thousand or two

thousand newtons and our actual value should be seven thousand or six thousand units

it would seem impossible that any person would be able to hold on to something that is accelerating at 96 meters per

second squared clearly the video game is unrealistic in this instant

finally i want to look at this picture here at this point there is no tension in the cable

for there to be tension the cable has to have a load on it in other words whenever you see a cable

for it to have tension it has to be tight i hope you enjoyed today's video

have a great day bye bye