Question #e9277

2 Answers
Aug 29, 2017

There is.


Now of course usain bolt will start the sprint from rest as we have practically seen.Thus, we can take the initial velocity as zero.

Assuming acceleration constant,




But if the acceleration isn't constant the information is insufficient as in that case, we have to integrate acceleration using the following formula:


Oct 11, 2017

Usain Bolt's average acceleration is 1.086 m/s^2.


We can manipulate the suvat formula
#s = u*t + 1/2*at^2#
and arrive at #a = (2(s - u*t)) / t^2#.
If we plug in our data, that will provide a value of acceleration that would take an object 200 m in 19.19 s.
So I will do that.

#a = (2(200 m - 0*19.19 s)) / (19.19 s)^2 = (400 m)/(368.25 s^2)#
#a = 1.086 m/s^2#

So that is Usain Bolt's average acceleration. That value of acceleration, would take an object 200 m in 19.19 s if used for the entire 200 m.

Usain Bolt could not use that strategy for that race. His speed would be up to only 3 m/s after 3 second of running while everyone else would be at their full speed. Usain could not actually maintain that value of acceleration in a 200 m because after 19 s that would have him running at about 19 m/s - or about 68 Kilometers per Hour. That is slightly faster than a cheetah in a chase.

So Usain Bolt - and all sprinters - uses maximum acceleration at the start to get up to full speed quickly and continue at a good pace throughout.

I hope this helps,