Status at this point for Einstein (and us)
Einstein’s Equivalence Principle proposes gravity and acceleration are equivalent
- Cleverly explains why gravitational mass = inertial mass
- It follows immediately that all bodies fall with same acceleration
- Important predictions such as “gravitational red shift”, bending of light in gravitational field
Now what to do about Newton’s laws:
- What replaces Newton’s Laws: 1. Inertia: Objects move in straight lines if there are no forces 2. F= Ma 3. Action/Reaction (Conservation of Momentum)
- What replaces forces (e.g., force of gravity)
- How to get around Newton’s problem of gravity as “action at a distance”