Simple Physics 12 Problem.
 

I'm looking at a simple Phys12 problem that my cousin asked me to help him with, but I'm surprisingly having some issues with it.

"Earth: m= 5.98e24 kg, moving at speed of 2.97m/s.
Sun: is 1.49e11m away, exerts a force of 3.56e11N on earth.

If the earth orbited the sun in a perfect circle, how much work would the sun do on the earth in one second?"


Who wants to earn some thanks? :thumbsup: Thanks in advance.

W = F x D
Fc = mv^2/r

majority of the numbers variables are already there EXCEPT D which you need to find work. Since D is distance. You get the formula D = v*t so in this case in one second you get 2.97m for the variable d.

Fc = (mass of earth * velocity of earth^2)/ distance from the sun.

The result of this equation shall me put in the W=F*D formula.

So we end up with W = Fc * 2.97.

I dont got a calculator handy but it should be right.

^

I originally thought that too, but doesn't the F have to be parallel to the motion ? In this case, it's perpendicular, since it's orbiting.

im glad i didn't take physics !

I think the solution above is correct
F = mv^2/r is the force exerted on Earth due to the Sun's gravity
and W = F d would give the work done on the Earth by the Sun for that distance, ie. one second.

It is a simple question, maybe just that the concept of gravity performing work is kinda confusing. Its not related to torque or anything so perpendicular or not doesnt matter. I hope I'm not wrong :)

it's 0. The force and velocity vector are always perpendicular.

bah my other post never posted...i was about to say to try plugging it into the whole work formula which is w= FDcos(theta). I forgot to add that sry =.=. I don't quite remember if it's perpendicular that there is no work exerted or no parallell. sorry dude.

yo it basic too bad you too dumb to do school you wast yor mom money