The 1992 world speed record for a bicycle (human powered vehicle) was set by Chris Huber. His time through the measured 200 m stretch was a sizzling 6.509 sec , at which he commented “Cogito ergo zoom!” (I think, therefore I go fast). In 2001, Sam Whittingham beat Huber’s record by 19.0 km/h. What was Whittingham’s time through the 200 m?

The distance covered,$\Delta x=200\mathrm{m}$ .

Time taken by Chris Huber, $\Delta t=6.509\mathrm{s}$.

Whittingham’s speed is more by $19.0\mathrm{km}/\mathrm{h}$.

Speed may be defined as the time rate of change in distance. The speed of the cyclist can be found using the given distance and time.

The expression for the speed is given as follows:

$\mathrm{Speed}=\frac{\mathrm{Distance}}{\mathrm{Time}}$

Using equation (i), the speed of Huber is calculated as follows:

$\begin{array}{c}\mathrm{Huber}\text{'}\mathrm{s}\mathrm{speed}=\frac{200\mathrm{m}}{6.509\mathrm{s}}\\ =30.727\mathrm{m}/\mathrm{s}\\ =30.727\times \frac{18}{5}\mathrm{km}/\mathrm{h}\\ =110.6\mathrm{km}/\mathrm{h}\end{array}$

Since Whittingham’s speed is more than Huber by ,

$\begin{array}{c}\mathrm{Whittinghams}\mathrm{speed}=110.6+19.0\mathrm{km}/\mathrm{h}\\ =129.6\mathrm{km}/\mathrm{h}\end{array}$

First, convert Whittingham’s speed in m/s.

Distance is given in meters to find time so that we will convert speed into m/s.

$\begin{array}{c}\mathrm{Whittinghams}\mathrm{speed}=129.6\mathrm{km}/\mathrm{h}\\ =129.6\times \frac{5}{18}\mathrm{m}/\mathrm{s}\\ =36\mathrm{m}/\mathrm{s}\end{array}$

The time for Whittingham through 200 m was calculated as follows:

$\begin{array}{c}\mathrm{Time}=\frac{\mathrm{Distance}}{\mathrm{speed}}\\ =\frac{200\mathrm{m}}{36\mathrm{m}/\mathrm{s}}\\ =5.55\mathrm{s}\end{array}$

Hence, Whittingham’s time through 200 m was 5.55 sec.