Question

An athlete completes a 100 m race in 9.8 seconds. What is his speed in $\frac{km}{h}$? Assume the athlete is running at a uniform speed.

Answer 1

Step 1: Given

Distance=100 m

Time =9.8 s.

Step 2: Formula used

Speed is given as,

$Speed=\frac{Dis\tan ce}{Time}$

Step 3: Calculation

Speed =$\frac{Dis\tan ce}{Time}.$

$$\begin{gathered} =\frac{100m}{9.8s} \\ =10.2\frac{m}{s}. \end{gathered}$$

Speed in $\frac{km}{h}$= ?

To get speed in $\frac{km}{h}$, multiply $10.2\frac{m}{s}$ with $\frac{18}{5}or3.6.$

Speed = $10.2\times 3.6=36.72\frac{km}{h}.$

Hence, Speed in kilometers per second = $36.72\frac{km}{h}.$