Question

The average distance between Earth and the Sun is 2.5 × 10¹¹m. (a) Calculate the average speed of Earth in its orbit (assumed to be circular) in meters per second. (b) What is this speed in miles per hour?

Answer 1

a)

$$v=\frac{2\pi r}{T}\\v=\frac{2\pi (2.5\cdot10^{11})}{365.2\cdot24\cdot3600}=5.0\cdot10^{4}\frac{m}{s}$$

b)

$$v=1.1\cdot10^{5}\ mph$$