vs=42kms⁻¹
vs=72kms⁻¹
vs=62kms⁻¹
vs=22kms⁻¹
Given:
Ms = 3×10⁵ Me
d = 2.5×10⁴ Re
Also Ve = 11.2Km/s = √(2GMe/Re)
Now for the sun earth system,
(1/2)mVs² - GMe m/Re - GMsm/(Re+d) = 0
Assuming Re << d and taking the value of GMe/R = 11.2²
Vs ≈ 42 Km/s