- #1
rickyjoepr
- 6
- 1
Homework Statement
an asteroid heading towards earth, has a speed of 7.25 km/s as it passes the moons orbit, kit misses Earth by 5000km. What is the speed at the closest point to earth?
The professor provided us with the solution, which should be 11.0 km/s, however when I do the calculation, using the given values, my number is way off.
Is there a conversion I should be doing that I may not know about?
Homework Equations
Conservation of energy for an asteroid is
(.5) mVi^2-((GmMearth)/Ri) = (.5) mVf^2-((GmM_earth)/Rf)
The Attempt at a Solution
Vi = 7.25 km/s
Ri = distance from the moon to Earth = 384,000km
Rf = radius of Earth + 5000km = 11400km
Mearth =5.972x10^24
G = 6.67384x10^-11
solve for Vf
Vf = SQRT[ Vi^2 + 2GMearth ((1/Rf)-(1/Ri))] = 260475.0801