Newton's Laws of Dynamics: Feynman's Physics Explained
Newton gave us a program for predicting the future. His second law, F = ma, is really a rule about change: it does not tell you where something is, but how its velocity will change in the next instant. If you know where an object is, how it is moving, and the forces on it, you can compute its position a moment later — then repeat, step by step, to trace its whole future path. It is a complete recipe for the motion of the universe, given the starting conditions and the forces.
The big idea
Know the forces and the starting point, and the future is determined.
Think about it
Why does the same push make a shopping cart speed up much faster than a loaded truck?
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