Name: 【TEDx】TEDxCaltech - Sanjoy Mahajan - Rote Learning Fragments the World
Uploaded: 2014-04-27T07:45:14.000Z
Duration: 10 min 15 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

In problem solving as in street-fighting: Rules are for fools!

Let's see how far we can go by bending rules

if you stuck your hand  out of a moving car --

There are at least two ways  that you can use

You could spend  10 years learning physics

and you write down  the Navier–Stokes equations:

the differential equations of fluid dynamics.

And then you spend another 10 years learning mathematics

the exact approach has produced paralysis,

This one has four times the area, twice the diameter,

how fast do they fall  relative to one another?

Or is the small one roughly twice as fast?

What do you believe? What does your gut tell you?

You don't have to agree  with your neighbor.

So, cheer if you believe that the big cone

will fall roughly twice as fast  as the small cone.

Cheer if you believe  that they'll be roughly comparable.

in science we have a supreme court: experiment.

What can we use  that experiment to tell us?

They fall in the same air. It has the same density.

The only things different  between the two cones

Well, the drag force is equal to the weight.

Because they were falling at a steady speed with no acceleration.

of the drag force without any force sensors.

So this one has four times as much paper as this one.

So it's four times heavier, four times the drag.

The conclusion: drag is proportional to area.

Not square root of area, not the square of the area.

That's the result  of our home experiment

without the rigorous  rigor mortis method.

of dimensional analysis, solves the drag force.

Subtitles ListPlay Video

【TEDx】TEDxCaltech - Sanjoy Mahajan - Rote Learning Fragments the World

applause

force

experiment

fuel