Question

The speed of the bus is $90\dfrac{{km}}{h}$. What is it’s speed in $\dfrac{m}{s}$?

Answer 1

Hint: Here this question belongs to the unit conversion topic, that is we have to convert the unit of speed from one form to another. We have to convert the unit of speed of the bus from $\dfrac{{km}}{h}$ to $\dfrac{m}{s}$ by multiplying or dividing the speed of the bus by certain numbers.

Complete answer:
$\dfrac{{km}}{h}$ and $\dfrac{m}{s}$ are the units to measure the speed of travelling bodies.
$\dfrac{{km}}{h}$ is used to measure the speed of bodies running at a faster pace and for a longer time duration. Whereas, $\dfrac{m}{s}$ unit is used to measure the speed of the bodies running at comparatively a lower pace and travelling for shorter distances.
Now, we are given the speed of a bus as $90\dfrac{{km}}{h}$ and we have to convert it to $\dfrac{m}{s}$.
 So, we will first change the kilometres unit into metres and then change the time duration unit from hours to seconds to attain the final answer.
Now, kilometres and metres are the units for length.
We know that each kilometre of length consists of $1000$ metres.
So, converting kilometers into metres, we get $90\dfrac{{km}}{h} = 90 \times 1000\dfrac{m}{h}$.
Simplifying further, we get,
$ \Rightarrow 90\dfrac{{km}}{h} = 90000\dfrac{m}{h}$
Now, we have to convert the time duration unit from hours to seconds. We know that each hour consists of sixty minutes and each minute in turn consists of sixty seconds. So, one hours equals $3600$ seconds.
Hence, we get,
 $ \Rightarrow 90\dfrac{{km}}{h} = \dfrac{{90000}}{{3600}}\dfrac{m}{s}$
Cancelling common factors in numerator and denominator, we get,
$ \Rightarrow 90\dfrac{{km}}{h} = 25\dfrac{m}{s}$
Hence, the speed of the bus in $\dfrac{m}{s}$ equals $25\dfrac{m}{s}$.

Note:
We have different units for solid quantity, liquid quantity and gaseous quantity. Every quantity has a measurement unit from the low quantity to the high quantity. While converting the unit of a quantity from one form to another form we have a standard value. By multiplying or dividing we can convert the unit of the quantity. We have a different system of measurement of a quantity.