(a) v = 100 m / 8.70 s
(b) constant acceleration (from zero) means that the average velocity during the acceleration phase is half of the final velocity
(v/2) t + v (9.58 - t) = 100 m
plug in v and solve for t
(c) average acceleration is v/t
(a) In 2009, Usain Bolt ran the last 100 meters of the 150-meter race in 8.70 seconds. What is Usain
Bolt’s speed?
(b) The world record for the 100-meter dash is 9.58 seconds (Bolt, 2009). Use the speed from part (a)
as his maximum velocity. Assume a sprinter accelerates at a constant rate up to their maximum
velocity, which is maintained for the remainder of the race, no matter how long it is. What is the
duration of the acceleration period at the beginning of the race?
(c) Determine the initial average acceleration in part (b)
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