Speed and Velocity

Question

Assume the Earth moves in a perfectly circular orbit around the sun, The earth's orbital speed around the sun is known to be 30 km/s. Light travels at the speed of 3 x 10⁸ m/s in free space. Evaluate:

1. the distance between sun and earth
2. how much time it takes for light to travel from sun to earth

Calculate the average velocity of the earth while moving around the sun over a duration of 1 year.

Answer 1

One of Kepler's laws states tht the orbital velocity = 2piR/T where R is the radius from the center and T is the period. To find R, rearrange and solve for R = 1.5E11 meters knowing that T=365 days.

D=speed * time so the time for light to travel from the sun to the earth = 1.5E11/3E8=.5E3 or 500 seconds