(adsbygoogle = window.adsbygoogle || []).push({}); Why do the centripetal and gravitational force equal each other in orbit??Also...

1. The problem statement, all variables and given/known data

Say for example, a problem wants us to find the mass of a planet. It gives us a satellite that orbits that planet with a radius of R and a period T. Now, I know how to solve this problem. You must set Fc = Fg.

But what I do not know is why the centripetal and gravitational force of these two objects must equal each other.

Also, a similar problem to that is one like this:

When you take your 1200 kg car out for a spin, you go around a corner of radius 57.6 m with a speed of 15.2 m/s. The coefficient of static friction between the car and the road is 0.84. Assuming your car doesn't skid, what is the force exerted on it by static friction?

Again, I already know how to solve this. You must set Fc = Ff ... mv^2 / r = Ff, and then you just plug in the given values into the mv^2 / r and that is your answer.

I do not know why in this case the centripetal force and the static friction must equal each other.

If someone could please explain this to me, I would feel so much better while taking the test tomorrow... My teacher goes through this stuff extremely fast.

2. Relevant equations

V = 2piR / T

Fc = mv^2 / r

Fg = Gm1m2 / r^2

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# Why do the centripetal and gravitational force equal each other in orbit?Also...

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