Physics Notes 91207
Review of Newton’s Law’s(see notes from 9/10/07)
Gravity is an attractive force between any two “massive” objects
For an object in free fall, one object is the earth and the other is the falling object.
Why do objects of a different mass fall at the same rate?
Galileo’s argument:
Gravity pulls harder on objects with more mass; however, objects with more mass
have more inertia.
These two factors cancel out to arrive at a massindependent rate of acceleration.
In general, the magnitude of gravitational force is:
F sub g = (G)(mass 1)(mass 2)
R^2
Where G = 6.674 x 10^11 Nm^2/kg^2, m1 and m2 are the masses of the two objects, and r is the
distance between their centers.
Since F sub y = (m sub 1)(a sub y) =  ((G)(m1)(msub E))/((R sub E + y(t))^2)
where R sub E is the
radius of the earth, m1 the mass of the falling object, cancels out s. t.
A sub y=(G sub mE)/ ((R sub E + y(t))^2) = (G sub mE)/R^2 sub E.
What is the value of A sub y?
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 Spring '08
 Schwarz
 Physics, Force, Gravity, Mass, General Relativity, gravitational forces

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