1. UNIT 7 - UNIVERSAL GRAVITATION Simplified Notes

2. GRAVITY IS UNIVERSAL  The moon is “constantly falling around the Earth.” It has velocity that keeps it moving in an orbit instead of crashing into the Earth.  Johannes Kepler – Came up with the laws of planetary motion. He described HOW the planets moved, but not WHY.  Newton explored the WHY. He decided that there has to be a force (GRAVITY) that keeps the planets moving in their elliptical orbits.

3. GRAVITY IS UNIVERSAL

4. USING THE LAW OF UNIVERSAL GRAVITATION – CALCULATOR TIPS

5. EXAMPLE: FINDING THE GRAVITATIONAL FORCE OF THE EARTH ON THE MOON

6. USING THE LAW OF UNIVERSAL GRAVITATION – CALCULATOR TIPS  You can put the whole thing in at once or separate it into 2 steps.  DON’T FORGET to square d!  Try the example problem in your calculator right now and make sure you understand how to get the right answer. Ask your classmates for help if you are having trouble. 1 Step 2 Steps

7. PRACTICE PROBLEM – TRY BEFORE RECEIVING HW  Joe (mass 95 kg) and Sue (mass 67 kg) are a mean distance of 0.75 m away from each other. Calculate the gravitational force that each of them exerts on the other.  When you think you have the answer, take it up to the teacher. If it is correct, he or she will give you your homework!