Comet Orbit Astrophyiscs question

[dgoudie]

Homework Statement

"Supposing that at perihelion a comet is 1 Au from the sun and its speed at that point is 200km/s( in a frame of referance in which sun is stationary). Find its mean PE and KE to one sig digit. Does it satisfy the virial theorem?

Homework Equations

K= .5mv^2
U=-GMm/r
Virial theorem:

The Attempt at a Solution

I know how to calculate U and K, and I know that at perihelion the V is at max, but will the K and U I find be the mean?

 

[member 553083]

Also, I am not sure how to calculate the Virial theorem. Any help would be greatly appreciated. K= .5mv^2 = .5(2.2x10^14)(200x10^3)^2 = 8.8x10^21 JU=-GMm/r = -(6.67x10^-11)(2.2x10^14)/1 = -1.5x10^4 JThe Virial theorem states that the sum of the kinetic and potential energies of a system are equal to twice the total energy. In this case, the total energy = K + U = 8.8x10^21 + (-1.5x10^4) = 8.8x10^21 - 1.5x10^4 = 8.79x10^21 JTherefore, the Virial theorem is satisfied.