I don't know which class your teaching but we learnt these conversion in primary school .And we are expected to do those all calculation in just one step. By the way your teaching skills are just awesome
The "Indian way is to "learn" mechanically by using short cuts without a thorough understanding of the principles. Mr Woo's method provides a better foundation
That was just his average speed, his peak speed was 40+ kmph. And if he wanted to make a record he would have run faster instead of celebrating before reaching the finish line
Differentiation is basically finding the Individual Components (IC) of the Whole and not restricted to finding the velocity. Integration is finding the Whole given the ICs and not restricted to finding the Area. So its all about ICs and the Whole and not just speed and areas.
And to think his overall top speed would be higher than that cause of course your dealing with averages in this case. Which is why it's good that you point out that his 150m race gave him a faster 100m time. Think it would give people an insight behind the magic of numbers I feel.