In a 100m sprint race, Usain Bolt accelerates out of the blocks and reaches a velocity of 6.92 m/s at the 20m point. What is Usain's acceleration out of the blocks?

1 Answer
Junaid Mirza
Nov 22, 2017

#"1.20 m/s"^2# (rounded up to 3 significant figures)

Explanation:

Use equation of motion

#v^2 - u^2 = "2aS"#

Here

  • #v# = Velocity of Usain Bolt when he reaches 20 m point (= #"6.92 m/s"#)
  • #u# = Velocity of Usain Bolt when he just started the race (= #"0 m/s"#)
  • #a# = Acceleration of Usain Bolt
  • #"S"# = Displacement covered by him when his velocity became 6.92 m/s

#a = (v^2 - u^2) / ("2S")= (("6.92 m/s")^2 - ("0 m/s")^2) / ("2 × 20 m") = "1.20 m/s"^2#

Related questions
Impact of this question
452 views around the world
You can reuse this answer
Creative Commons License