A line drawn from the Sun to a Planet
will sweep out equal areas in equal times.
t 1 = t2
t2
A1
A2
A1 = A2
t1
The radius of a planets orbit cubed ( r3 )
Divided by the period of orbit squared ( T2 )
IS A CONSTANT !
3
r=
2
T
k
used the
Centripetal Force Eq