Good,+Bad,+and+Ugly+Physics

= ﻿﻿THE GOOD, THE BAD, AND THE UGLY of Physics = =// ﻿ //= =media type="youtube" key="gDV9T74CYvE" height="363" width="562"= =__ The Good. __= Warning: Only watch until exactly 0:12, unless you want to see this guy break his legs

Alright, so this guy jumps off of a ski lift, which must be at the prime height in its cycle. I did some research and found that a normal ski lift at its highest point is about 40 meters (we will use this for "d" in our distance formula).

Since the guy slid off the ski lift, not jumping with any speed, we can say that his initial velocity is 0.

We also know the known value of the acceleration of gravity (9.8 m/s squared).

Using a stopwatch, I timed how long it took for the man to jump and hit the ground 3 times, and got an average of 2.51 seconds.

Using the equation: d=vit + (1/2)at^2 We plug in "d" (40 meters), "vi" (0m/s), and "a" (9.8m/s) we will solve for "t" to see how close it is to our known value of 2.51 seconds.

Solving for t in the equation, we get: t= (d-vit / (1/2)a) ^1/2 SO we calculate: t=((40-0) / (.5x9.8))^1/2 = = We get... t=2.85 seconds. Now considering the time that I took in the beginning (2.51 seconds), this is only an error of .3 seconds. That's pretty darn GOOD PHYSICS for a movie!

= = = media type="youtube" key="JliKh_USZDM" height="349" width="560" = = = =__ The Bad. __= In Physics class, we learned that the standard light bulb in the United States has a frequency of 120 Hz. This means that they flicker on and off 120 times per second.

In the movie //Inception//, it is quoted that time goes by slower in dreams. "5 minutes in the real world is an hour in the dream world". So essentially, time would go by 20 times slower while we dream.

Therefore, the makers of //Inception// have made a bad mistake in the physics of their movie. In this clip, the man floating around in the hotel is in a dream, so time is going by 20 times slower. Technically, since time is slowed down, we should be able to notice the fluorescent lights in the hotel flickering on and off.

Solving the proportion of __5min__ =__1min__ 60min xmin We find that 1 minute in the real world equals 12 minutes in the dream. Or, 1 second in the real world equals 12 seconds in the dream. Considering that fluorescent bulbs flicker at a rate of 120 times/ second, in the dream, the light should flicker 120 times/ 12 seconds. Watching this scene, we should notice the lights flickering 6 times every second. When we see these lights, they appear no different, so therefore this is BAD PHYSICS.

= = = = = = = = = = =media type="youtube" key="f8mLJs-lMTw" height="349" width="560"= =__ The Ugly. __= Watch 2:30-2:53

I thought it was quite unrealistic that a spatula, probably stainless steel, would bend that much from the weight of a hamburger (even if it is a huge burger)

[|http://www.matweb.com] states that stainless steel has a compressive yield strength of 262 Mega pascals (meaning it can take 262Mpa until it bends). Converting this into pascals, we multiply 262 x 10^6 (to bring Mega to Deka). We get 262,000,000 pa. We are going to use this number as "P" in our pressure equation, P=F/A.

I measured a standard restaurant-style spatula to have a 2mmX10mm cross section on its handle. The handle is rectangular, so by multiplying the dimensions we find a cross-sectional area of 20mm squared. Dividing by 1000 twice, we find that the area of is: .00002 m squared.

Well we have Pressure (262000000pa) and Area (.00002m squared). So now, we solve for Force. F=PA, so we multiply 262000000 x .00002 = 5240 N.

To convert to pounds we use the conversion factor of 1pound=.224808943 newtons 5240 x .224808943 = 1177.99 Lb

Wow. In order to get the spatula to bend like that, the burger would have to weigh AT LEAST 1178 pounds. That's a huge burger.

This is UGLY PHYSICS.

The end.

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