Newton’s Law of Universal Gravitation
5-5
Quick notes
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Reading Questions
1. Why was Newton’s Theory of gravity hard to accept at the time (why did
people have difficulty with the idea that a force keeps the moon tied to the
Earth)?
2. What is the centripetal acceleration of the moon?
3. The acceleration of the moon toward the Earth is about _______________as great
as the acceleration of objects at the Earth’s surface
(.00272m/s2/9.8m/s2g=1/3600g) .
4. The moon is ________ times further from the Earth’s surface than objects on
the Earth’s surface.
5. ______________2 = 3600! So FG is inversely proportional to the square of the
distance an object is from earth! Written:
6. In other words the farther an object is from the earth the _________the force of
gravity by ___________________.
7. The force of gravity is ____________________ __________________________ to an object’s
mass. This comes from Newton’s ______________law. ( equal and
_______________________)
8. The magnitude of gravity is proportional to _______________ _____________ masses.
9. So the equation for the force of gravity between two object’s is :
10. This leads to the law of universal gravitation which states:
11. Called the inverse square law it is written:
12. What is the value of the constant G?
13. Who first calculated the value of G?
14. Look at Example 5-9. Can you attract another person gravitationally? Look
at the solution and describe it below:
15. Look at Example 5-10 and notice the easier way to calculate this problem.
Explain how you could use this to calculate that Force of gravity on the
spacecraft.
Do problems 28 , 31 and 40 below: