College Physics Problem 1.10

Solution:

Part a

We assume that the earth revolves around the sun in a circular manner. Therefore, the distance between the earth and the sun will be the radius of its orbit.

The total distance traveled the earth in full revolution is

$\displaystyle d=2\pi r$

$\displaystyle d=2\pi \left(10\right)^8\:km$

The total time of travel is

$\displaystyle t=365.25\:days\left(\frac{24\:hr}{1\:day}\right)\left(\frac{3600\:s}{1\:hr}\right)=3.15576\times 10^7\:sec$

Therefore, the average speed is

$\displaystyle v=\frac{distance}{time}=\frac{d}{t}$

$\displaystyle v=\frac{2\pi \left(10\right)^8\:km}{3.15576\times 10^7\:s}$

$\displaystyle v=19.91\:km/s$          ☚

Therefore, the average velocity of the earth is 19.91 km/s.

Part b

Convert 19.91 km/s to m/s.

$\displaystyle v=\left(19.91\:\frac{km}{s}\right)\left(\frac{1000\:m}{1\:km}\right)=19910\:m/s$          ☚

Therefore, the velocity is 19910 m/s.