Question

How do you convert \[\text{73 mi/h = }\!\!\_\!\!\text{ }\!\!\_\!\!\text{ }\!\!\_\!\!\text{ }\!\!\_\!\!\text{ km/s}\]?

Answer 1

Hint: In this question we have given speed with the unit of miles per hour which we have to convert to the unit’s kilometer per second. We will use the conversation from a mile to a kilometer and the conversion of hour to second. We will use the relationship $\text{1 mile = 1}\text{.61 km}$ for converting the miles into kilometers and we will convert hour into seconds and divide both the values to get the result in $\text{km/h}$.

Complete step-by-step solution:
We have been given the value $\text{73 mi/h}$ which we have to convert into $\text{km/s}$.
We have the relationship that $\text{1 mile = 1}\text{.61 km}$.
Therefore, the total number of kilometers are:
$\Rightarrow 73\times 1.61$
On simplifying, we get:
$\Rightarrow 117.53$
Now we know that an hour constitutes $60$ minutes and each minute constitutes $60$ seconds therefore in $1$ hour the number of seconds, will be:
$\Rightarrow 60\times 60$
On simplifying, we get:
$\Rightarrow 3600$
So, we have:
$\Rightarrow \text{73 miles/hr = }\dfrac{117.53}{\text{3600}}\text{ km/s}$
On simplifying, we get:
$\Rightarrow \text{73 miles/hr = 0}\text{.0326 km/s}$, which is the required solution.

Note: It is to be remembered that speed tells us how fast an object moves. Its formula is distance upon time. The distance can be measured in meters, kilometers, yards, miles etc. time can be measured in hours, seconds, minutes etc. A more accurate way of getting the speed will be using $\text{1 mile = 1}\text{.60934 km}$. The shortcut formulas should be remembered such as we can convert miles per hour to meters per second by multiplying $4/9$, we can convert meters per second to kilometer per hour by multiplying $18/5$and convert back by multiplying it with $5/18$. The standard unit of speed is meters per second.