Physics I: Classical Mechanics #1

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 1024 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”.

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