- #1
bobbricks
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I'm confused on how you get the formula v=root(2GM/R²). I know you can use work=forcexdisplacement (W=Fd) so F=W/d.
W=½mv² and R=d. Hence, F=½mv²/R
Equate that to F=GmM/R² and rearrange to get v=root(2GM/R²).
That makes sense as it involves the kinetic energy needed/work done in reaching orbit (or is it for escaping orbit?).
However, why can't you use the formula F=mv²/R and equate that to F=GMm/R² ? It gives you v=root(GM/R²). That's slightly different to the formula that involves kinetic energy.
W=½mv² and R=d. Hence, F=½mv²/R
Equate that to F=GmM/R² and rearrange to get v=root(2GM/R²).
That makes sense as it involves the kinetic energy needed/work done in reaching orbit (or is it for escaping orbit?).
However, why can't you use the formula F=mv²/R and equate that to F=GMm/R² ? It gives you v=root(GM/R²). That's slightly different to the formula that involves kinetic energy.