Question

How long will it take you to drive $135$ miles at a speed of $45$ miles per hour?

Answer 1

Hint: We know that the speed traveled could be calculated as distance covered by the time taken. We can also say that the average speed is nothing but the displacement divided by the time taken. Speed is a scalar quantity. Speed contains only one direction and no magnitude. We can calculate the time taken by dividing the distance traveled by the speed. ${M^0}{L^1}{T^{ - 1}}$ is the dimensional formula of speed.

Complete step by step answer:
Given data contains,
Distance covered is $135$miles.
Speed is $45$ miles per hour.
We know that the mathematical expression average speed could be given as,
${\text{Average Speed = }}\dfrac{{{\text{Distance}}\,{\text{travelled}}}}{{{\text{Time}}\,{\text{taken}}}}$
Rearrange the above equation to get the time taken.
${\text{Time taken = }}\dfrac{{{\text{Distance}}\,{\text{travelled}}}}{{{\text{Speed}}}}$
From the speed and distance covered, we have to calculate the time taken.
Let us now substitute the values of distance traveled and speed in the equation.
Time taken=$\dfrac{{Dis\tan ce\,travelled}}{{Speed}}$
Time taken=$\dfrac{{135miles}}{{45miles/hour}}$
Time taken=$3hr$
We have calculated the time taken to drive $135$ miles at a speed of $45$ miles per hour as $3hr$.

Note: The unit of speed is $m{s^{ - 1}}$ in the SI unit of the system and in the CGS system the unit of speed is $cm.{s^{ - 1}}$. We can also say that the ratio of distance covered to the time taken is known as speed. For the estimation of speed in vehicles, speedometers are utilized. To quantify the distance covered odometers are utilized. Speed can likewise be determined with the assistance of a chart. The Distance-time diagram helps in understanding the speed of an article. There are four sorts of speed and they are:
1. Uniform speed
2. Variable speed
3. Normal speed
4. Momentary speed