The earth moves around the sun in a nearly circular orbit of radius 1.50 x 1011 m. During the three summer months (an elapsed time of 7.89 x 106 s), the earth moves one-fourth of the distance around the sun. (a) What is the average speed of the earth? (b) What is the magnitude of the average velocity of the earth during this period?

Answer 1

avgspeed=distace/time

distance=2PIr
time: 1 year, convert that to seconds if you want m/s

average velocity: (Vf+Vi)/2 but vf, Vi are at ninety degrees, so magnitude is Vf*sqrt2/2=.707V