Mercury orbits the sun with an average speed of 4.78 x 104 m/s. About how long does Mercury take to orbit the sun once if the radius of its almost circular orbi

Question

Mercury orbits the sun with an average speed of

4.78 x 10⁴ m/s. About how long does Mercury take to orbit the sun once if the radius of its almost circular orbit is 5.79 x 10¹⁰m?

Answer 1

Since the radius of its (almost) circular orbit is 5.79 x 10¹⁰m, then mercury travels 2*pi* 5.79 x 10¹⁰m during a single orbit.

 

T = distance/speed =  2*pi* 5.79 x 10¹⁰m/ (4.78*10⁴ m/s).  = 7.61 *10⁶s  or 0.241 years.