Question

In a race, usain bolt starts from the rest and accelerates at 1.99 m/s^2 for the first 60.0 m. he then decelerates at -0.266 m/s^2 for the final 40.0 m. what was his final velocity

Answer 1

Usain Bolt's final velocity in the race was 15.71 m/s.

Step-by-step explanation:

To find Usain Bolt's final velocity, we can use the equations of motion. First, let's calculate the time it takes for him to accelerate to his maximum speed of v:

• v = u + at
• 0 = 0 + 1.99(3) (since he starts from rest)
• t = 9.00 s

Now, let's find his maximum speed:

• v = u + at
• v = 0 + 1.99(9.00)
• v = 17.91 m/s

Finally, let's find his final velocity:

• v = u + at
• v = 17.91 - 0.266(7.00)
• v = 15.71 m/s