# Classical Mechanics

1. Feb 23, 2015

### Shreyas Samudra

In classical physics , specifically in rotational mechanics we have concepts of torque , angular momentum and their extensions. We widely use them in problem solving but how were they defined , what was the basis of their definition , was all that purely experimental and most importantly who did that ?

2. Feb 23, 2015

### CWatters

Aristotle (384-322 B.C) might be the earliest writing but the principles of levers must have been known 1000's of years earlier.

Edit: Archimedes also (287-212 BC)

3. Feb 23, 2015

### Andrew Mason

Welcome to PF Shreyas!

Any quantity that is conserved in an interaction will be useful because it allows us to predict what the results of an interaction will be. Since momentum, energy, angular momentum will be conserved interactions, in the absence of external effects such as external force or external torque or external energy sinks, these quantities will be important. When these quantities change due to external effects, the rates of change will be important to keep track of (Force = dp/dt = dE/dx; Torque = dL/dt;) in order to determine the final values.

You should study the history of science/physics to better appreciate how these concepts evolved. These concepts were developed due to the work of many great scientists.

AM

4. Mar 4, 2015

### Shreyas Samudra

where may i find that ? some link ........

5. Mar 8, 2015

### Shreyas Samudra

I actually mean to ask, how is a particular physical quantity defined so that it rightly describes quantum of a physical interaction ?