Question

Every year, the earth travels about ${10}^9$km as it orbits the sun. What is the earth’s average speed in km/h?

Short answer

The earth’s average speed is $1.14\times {10}^5\frac{\mathrm{km}}{\mathrm{h}}$.

Step-by-step solution

Step 1. Calculation of the total hours in one year

The earth’s orbit is a two-dimensional plane in which it rotates around the sun. The earth takes 365 days to complete one complete cycle in its orbit.

Given data.

The traveled distance of the earth in a year is ${10}^9\mathrm{km}$.

Now, you know that there are 365 days in a year and 24 hours in a day. Then,

$\begin{array}{c}1\mathrm{year}=365\mathrm{day}\\ =365\mathrm{day}\times \frac{24\mathrm{hour}}{1\mathrm{day}}\\ =8760\mathrm{hour}\end{array}$

Step 2. Calculation of average speed

Now, you know that

$\begin{array}{c}\mathrm{Average}\mathrm{speed}=\frac{\mathrm{Total}\mathrm{distance}}{\mathrm{Total}\mathrm{time}}\\ =\frac{{10}^9\mathrm{km}}{8760\mathrm{h}}\\ =1.14\times {10}^5\frac{\mathrm{km}}{\mathrm{h}}\end{array}$

Therefore, the earth’s average speed is $1.4\times {10}^5\frac{\mathrm{km}}{\mathrm{h}}$.