Question

Speed of \[90\] km/hr when expressed in m/s is

Answer 1

Hint:The given speed is in a kilometer per hour we need to express that in terms of meter per second by using unit conversion formulas.
We first convert the kilometer per hour to a kilometer per second and then we will convert the kilometer per second to meters per second.
Formula: Some unit conversion formulas that we need to know:
\[1\]kilometer\[ = \]\[1000\] meters
\[1\]minute\[ = \] \[60\] seconds
\[1\]hour\[ = \] \[60\] minutes

Complete step by step answer:
It is given that the speed is a \[90\] kilometer per hour. We aim to convert this speed to a meter per second.
We will use the unit conversion formulas to convert the given speed.
The given speed is in kilometers per hour. To convert it to meters per second we need to multiply the speed by\[1000\] and divide it by \[60 \times 60\].
Since by the formula, the \[1\]kilometer is equal to \[1000\]meters so we need to multiply the speed by \[1000\] and again by the formula we have that \[1\] minute is equal to \[60\] minutes and \[1\] hours is equal to \[60\]minutes so \[1\] can be written as \[60 \times 60\] seconds.
Now let us calculate the problem.
\[90\]\[km/hr\]\[ = \]\[\dfrac{{90 \times 1000}}{{60 \times 60}}\]\[m/s\]
Let us simplify this.
                     \[ = \dfrac{{3 \times 1000}}{{2 \times 60}}m/s\]
On simplifying this further we get
                     \[ = \dfrac{{1000}}{{2 \times 20}}m/s\]
Let us again simplify this.
                     \[ = \dfrac{{100}}{{2 \times 2}}m/s\]
On simplifying this we get
\[90km/hr = \dfrac{{100}}{4} = 25m/s\]
Thus, the speed \[90km/hr\]can be written as \[25\] in meters per second.

Note: In unit conversion, when we are converting higher units to lower units, we will be using multiplication and in converting smaller units to higher units we will be using division.
Here we have converted kilometer to meter and hour to seconds by multiplying.