The formula used for finding the tangential speed (speed of something that is moving in a circular path) of an orbiting object is:
V₍t₎ = ωr
V₍t₎ = tangential speed or velocity
ω = angular velocity
r = radius of the circular path
if time taken t is only given then use this formula to calculate the tangential speed:
V₍t₎ = 2πr/t, t is time taken
