Find centripetal acceleration with two masses and radius.

AI Thread Summary
To find the centripetal acceleration between the Sun and Venus, the gravitational force equation Fg = G mv ms / r^2 is used, where mv is the mass of Venus, ms is the mass of the Sun, and r is the distance between them. The centripetal acceleration is expressed as ac = mv v^2 / r, linking gravitational force to centripetal acceleration. A misunderstanding arises when equating force and acceleration; the correct relationship is F = ma. The discussion highlights confusion over the necessity of calculating velocity (v) when centripetal acceleration is the primary goal. Clarifying these equations is essential for accurate results in calculating centripetal acceleration.
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Homework Statement


We are given the mass of the sun, ms = 1.99 x 10^30 and the mass of the venus, mv = 4.83 x 10^24. The distance from each other radius is r = 1.08 x 10^8.

What is the centripetal acceleration?

mv = 4.83 x 10^24 kg
ms = 1.99 x 10^30 kg
r = 1.08 x 10^8 km
G= 6 67x10^-11 N m2 /kg2

Homework Equations



Force of gravitational attraction
Fg = G mv ms / r^2

Centripetal Acceleration
ac = mv v^2 / r

The Attempt at a Solution



Since gravity causes the centripetal acceleration:
Fg = mv ac
G mv ms / r^2 = mv v^2 / r

Solving for v we get
v =\sqrt{} ms G / r

I am not getting the right answer, what is wrong with using these equations?
 
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2much said:
Since gravity causes the centripetal acceleration:
Fg = ac
G mv ms / r^2 = mv v^2 / r

Force does not equal acceleration. F=ma. See if that fixes the problem.
 
spikethekitty said:
Force does not equal acceleration. F=ma. See if that fixes the problem.

I did have mv in the final equation, just forgot to mention it there. Still didn't give me the answer of 1.3x10^-2 m/s2
 
hi 2much! :smile:

(try using the X2 tag just above the Reply box :wink:)
2much said:
Solving for v we get …

why are you finding v ? :confused:
 
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