- #1
shounakbhatta
- 288
- 1
Hello,
Consider a cylindrical region (length dr, end area dA) at a distance r from the center of the sun
Density =ρ(r)
Volume = Length x area = dr.dA (How is the formula for volume of a cylinder works here?)
Mass= Density x Volume = ρ(r).dr.dA
Now, computing F(grav) = -G.m(r).dm/r^2...we get F(grav)=-g(r)ρ(r)drdA. I understand up to that.
But the net pressure equation shows:
F(press)=(P(r+dr))- P(r))dA)
Can you please explain me how the above equation arrives?
Thanks
Consider a cylindrical region (length dr, end area dA) at a distance r from the center of the sun
Density =ρ(r)
Volume = Length x area = dr.dA (How is the formula for volume of a cylinder works here?)
Mass= Density x Volume = ρ(r).dr.dA
Now, computing F(grav) = -G.m(r).dm/r^2...we get F(grav)=-g(r)ρ(r)drdA. I understand up to that.
But the net pressure equation shows:
F(press)=(P(r+dr))- P(r))dA)
Can you please explain me how the above equation arrives?
Thanks