Question 331605
t=2pi sqrt((r^3)/(gm))

Divide both sides by 2Pi


T/2Pi = sqrt(r^3/gm)


Square both sides:


(T/2Pi)^2 = r^3/gm


Multiply both sides by m:


m*(T/2Pi)^2 = r^3/g


Divide both sides by (T/2Pi)^2:

m = (r^3/g)(2Pi/T)^2



Next question: a/b + c= a/d

a/b=a/d -c
a = (a/d-c)b
a/(a/d - c) = b


Last question: d = vt + (1/2)at^2

d = vt + (1/2)at^2
d - (1/2)at^2 = vt


Divide both sides by t:


d/t - (1/2)at = v