Olympic sprinter Usain Bolt set the world record in the 100 meter dash with a time of 9.58 seconds. The phyics behind his performance are impressive. Physicists have modeled his position as a function of time to be as follows:
x(t)= A/k ln (A+Be ^-kt/ A+B) +B/k ln (Ae^kt + B/A+B)
where A=110 m/s, B=12.2 m/s, k=0.91 m/s. Using this information, find his acceleration when t= 0 seconds. If his mass was 86 kg at the time of the race, what was his force at t=0 seconds. What was the force from the ground on Bolt at t=0 seconds?