Question

(a) A world record was set for the men’s 100-m dash in the 2008 Olympic Games in Beijing by Usain Bolt of Jamaica. Bolt "coasted" across the finish line with a time of 9.69 s. If we assume that Bolt accelerated for 3.00 s to reach his maximum speed, and maintained that speed for the rest of the race, calculate his maximum speed and his acceleration

Usain Bolt's maximum speed is calculated as:
(a) 9.69 m/s, 3.23 m/s²
(b) 9.69 m/s, 2.05 m/s²
(c) 10.00 m/s, 3.00 m/s²
(d) 10.00 m/s, 2.00 m/s²

Answer 1

Usain Bolt's maximum speed in the men's 100-m dash is 9.69 m/s and his acceleration is 3.23 m/s².

Step-by-step explanation:

To calculate Usain Bolt's maximum speed and acceleration, we can use the equations of motion. Bolt accelerated for 3.00 s before reaching his maximum speed, which means his initial velocity was zero. His final velocity would be his maximum speed. We can use the formula v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time. Bolt's maximum speed would be the final velocity.

So, v = 0 + a(3.00 s), which simplifies to v = 3a. We know that Bolt crossed the finish line with a time of 9.69 s, and during this time, he maintained his maximum speed. Therefore, his maximum speed can be calculated as: 9.69 s = 3a. Solving for a, a = 9.69 s / 3 = 3.23 m/s². His maximum speed would then be 3 times his acceleration, which is 3.23 m/s² x 3 = 9.69 m/s.