12/04/2006

Physics and movies

These directors should be taught some physics.

In school and college, we are taught, diligently enough, that the acceleration due to gravity g acts downward (towards the center of the earth, that is). These movies seem to fill in for the other two cases, g acting upward, and a zero value for g. The former being in fight sequences where people just seem to rise out of nowhere. The latter when people just float for 10 odd metres. Whatever happened to the projectile motion we learnt. Also, I always thought work done by static friction was zero. But that doesn't seem to explain how a certain somebody, on getting a horizontal impulse jumps up and lands on the same place. Next, consider this problem: Bodies A and B are on top of a cliff. A is dropped. B is dropped 10 seconds later. Can B catch up with A? Assume B and A similar in all respects, same air resistance etc. The answer is Yes. If B is the good guy and A is the bad guy. Now, consider conservation of momentum. When A shoots B, the recoil A experiences is a few centimetres, due to the change in velocity of the bullet from zero to the maximum value, but on hitting B, due to the same momentum decrease (Maximum value to zero), B is thrown a few metres backwards. This either means one of the guys weighs in milligrams, or in tonnes. Oh, and I don't understand this: When you cut a guy's head (Kill bill kind), the head is cut due to shear force right? Then why the hell does the head fly off?
Bah, there are too many problems out here.

7 comments:

Mahesh Mahadevan said...

Your answer is here.

Mohan K.V said...

But verily, my dear friend, our Education System is trying its very best (?) to ensure that such occurences are indeed rationalized..

I would refer you the valiant efforts of one of our very own professors to introduce us to the concept of relativity and length contraction in Modern Tamizh movies.

Yo maan, I'm talkin' 'bout da Pal Pandi and da Minnal clip!

Anonymous said...

too good.

dushy said...

Wow effect!
How abt the chemistry in movies?Do write on that! :-))

Anonymous said...

some contributions:
If A jumps a few seconds after B from a height, and they are both in a free fall, then A can catch up with B, assuming that he is well trained
Experienced skydivers can manipulate the air resistance acting on them by changing their body position, angle of attack, etc and stuff like that. but B should be inexperienced enough to let A catch up, and both should be high enough so as not to hit the ground while they are busy with the chase.

Anonymous said...

Dei, why are you so much bothered about physics in movies? Don't try to break your head over such stuff. Just enjoy the stuff, rofl at it and leave. After all, it is for entertainment, isn't it?

Forget physics. Look at the way they portray how people fall in love in movies. Probably that too needs a post from you.

Govar said...

No. I disagree. They dont need physics. They need commonsense, which isn't, apparently, common place.