Question

Express the following speed in km/hr. 2 m per second.

Answer 1

Hint: We will change the m per sec and km per hr using the conventional way where we will change the value of meter to kilometer and hour to seconds and get the desired answer.

Complete step-by-step answer:
To get the the speed in the different units first we have to know some basics things ,that is
\[1\text{ km}\,=1000\text{m} \]
\[\text{1m}=\,\dfrac{1}{1000}\text{km} \]
\[\text{1 minute}=1\,\text{hour} \]
\[ \text{1 minute}=60\,\,\text{seconds} \]

\[ \text{1second}=\dfrac{1}{60}\text{ minute} \] 
 \[\text{1hour}=60\text{ minute} \] 
 \[\text{1hour}=\,60\times (60\,\text{seconds}) \]
 \[1\text{hour}=3600\,\,\,\text{seconds} \]
Thus we will use these basic concepts to change the unit of meter per second to kilometer per second.
\[ \text{1 km/hr}=\dfrac{1\text{ km}}{1\text{ hr}}=\dfrac{1000\text{ m}}{60\times (60\,\text{seconds})}=\dfrac{1000\text{ m}}{3600\,\,\,\text{seconds}}=\dfrac{5\text{ m}}{18\,\text{second}} \]
\[ \dfrac{5}{18}\text{m/sec}=1\,\text{km/hr} \]
\[ \text{1}\,\text{m/sec}=\dfrac{18}{5}\text{km/hr} \]
\[ \text{2m/sec=2}\times \dfrac{18}{5}\text{km/hr}=\dfrac{36}{5}\text{km/hr} \] 
\[ \dfrac{36}{5}\text{km/hr} \] 
Thus, the change in unit for 2 meter per second into kilometers per second will give us the value of \[\dfrac{36}{5}\text{km/hr}\].

Note: The unit ‘\[\text{km}\]’ is for a kilometer in distance. The unit ‘\[\text{hr}\]’ is hour in time . The unit ‘\[\text{m}\]’ is meters in distance. The unit ‘\[\text{sec}\]’ is for second in time. \[\text{km/hr}\] is kilo-meter per hour for speed and \[\text{m/sec}\] is for meter per second for speed as well. We first changed 1 kilometer per hour to meter per second. After changing it to meter per second we tried to find out the value of 1 meter per second through it. After getting the value of 1 meter per second we just need to multiply the value given to us in the question which needs to be changed. The value which needs to be changed here is 2 meter per second. Thus we multiply 2 with the value we found out for change from 1 meter per second to kilometer per hour.