## 8.01 Physics I: Classical Mechanics

### Lecture #1: This lecture is about units, dimensions, measurements and associated uncertainties, dimensional analysis, and scaling arguments.

Instructor/speaker:

Prof. Walter Lewin

View the complete course at:

http://ocw.mit.edu/courses/physics/8-01-physics-i-classical-mechanics-fall-1999/

License: Creative Commons BY-NC-SA

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#### Physics 1: Classical Mechanics Notes

Length = meters

Time = sec

Mass = kg

Profressor references a video entitled “The Powers of Ten” by Charles and Ray

Eames and Pyramid Media. After some searching I found the video, it displays 40

powers of 10 with the 1st power 1 meter from a man having a picnic in a park. At

1 x 10^{24} it shows an image at the far reaches of space, the farthest mapped universe. The video then takes you back to the 1st power, and than goes

into negative powers until you reach 1 x10^{-15} in which you are at a

single proton.

Length Time and Mass are the 3 fundamental qualities in physics.

L T M

All other quantities in physics can be derived from these fundamental

quantities.

Examples:

The dimension of speed:

[ speed ] = [ L ] / [ T ] (the dimension of length divided by the dimension of time)

Volume:

[ volume ] = [ L ] ^{3} (length to the power three)

Density:

[ density ] = [ M ] / [ L ] ^{3} (length to the power three.)

Acceleration:

[ accel] = [ L ] / [ T ] ^{2} (length divided by time squared.)

All other quantities can be derived from these 3 fundamentals. (Length Time

Mass)

The professor states that: “Any measurement that you make without the knowledge

of its uncertainty is completely meaningless”.

JUN