When you have a rate of motion, such as feet per seconds, or miles per hours, you can use the important relationship
rate × time = distance
to solve many problems.
Example 1:If you ride your cycle at a speed of miles an hour in a straight line, how far will you be from your starting place after hours?
The rate is , and the time is hours.
So, you will be miles from your starting place.
Example 2:Light leaving the Sun takes about minutes to reach the Earth, traveling a distance of approximately miles. Find the speed of light in miles per second.
The rate is unknown. The time is minutes and the distance is miles.
Set up an equation.
Divide both sides by minutes.
Divide by to reduce the fraction.
Divide by to get miles per second.
So the speed of light is about miles per second.