Question

Convert a speed of $54$ km per hour into metres per second.

Answer 1

Hint: At first we find relation between km and meter which is $1km = 1000m$ and relation between hour and minute which is $1hour = 60\text{minutes} $ again relation between minute and second which is $1\text{minutes} = 60\text{seconds} $ . Convert the given kilometer into metre and the given hour in minute and minute in the second step by step and we get the solution.

Complete step by step answer:
Here we know $1km = 1000metre$
From the given data , we express km in meter
$ \Rightarrow 54km = 54 \times 1000metre$
$ \Rightarrow 54km = 54000metres$
And we also know $1hour = 60\text{minutes} $ and $1\text{minutes} = 60\text{seconds} $
We express $1hour$ in second and we get
Therefore , $1hour = 60 \times 60\text{seconds} $
$ \Rightarrow 1hour = 3600\text{seconds} $
From above we get $1$ km per hour $ = \dfrac{{1000}}{{3600}}$ meter per second
Therefore from the given data , we calculate the $54$ km per hour in metre per second , we have
$\therefore 54$ km per hour $ = \dfrac{{54000}}{{3600}}$ meter per second
Calculate above , we get
$ \Rightarrow 54$ km per hour $ = 15$ meter per second
Therefore, $54$km/hr = $15$ m/sec.

Note:
We can also solve the given problem by using the like , we find the value $1$ km per hour $ = \dfrac{{1000}}{{3600}}$ meter per second
Therefore , $54$ km per second $ = 54 \times \dfrac{{1000}}{{3600}}$ meter per second
$ = 15$ metre per second .