Velocity in the Olympics 100 Meter Dash

Learning Intentions

  • To learn how to calculate average velocity

Questions

  1. In the 1988 Olympics in Seoul, South Korea, Canada’s Ben Johnson set the men’s 100m world record by sprinting 100.00 m in 9.79 seconds. What was his average velocity for the race?Ben Johnson Olympic Final 1988 (0:51)
    • Johnson, who crossed the finish line first, tested positive for steroids, and had his gold medal stripped from him.
    • Carl Lewis, who tested positive in the qualifier for inadvertently high levels of performance enhancing drugs due to his use of the Chinese herbal medicine ma huang (a.k.a. ephedra sinica), won the gold medal with a world-record time of 9.92 seconds.
    • Carl Linford, who was later banned from competition for life for his use of performance enhancing drugs, won the silver medal.
    • Calvin Smith won the bronze medal. Never in his career did he test positive. He later said, “I should have been the gold medallist”.
    • Dennis Mitchell came in 4th. In 1998, his testosterone levels tested above the limit. In 2008, he testified that his coach injected him with human growth hormone.
    • Robson da Silva came in 5th. He never tested positive.
    • Desai Williams, also of Canada, came in 6th. He admitted that he was on steroids “briefly” in 1987.
    • Ray Stewart came in 7th. He never tested positive as a runner, but as a coach he received a lifetime ban in 2010 for procuring performance enhancing drugs for his athletes.
  1. In the 2008 Olympics in Beijing, China, Jamaica’s Usain Bolt set the men’s 100m world record by sprinting 100.00 m in 9.69 seconds.
    1. What was Bolt’s average velocity for the race?Usain Bolt 100 meter world record 9.69 seconds (0:20)

      • In his career, Bolt never tested positive, although he was stripped of his 4 x 100m relay gold medal from the 2008 Beijing Olympics after his teammate Nesta Carter tested positive for a banned stimulant.

    2.  For the first 50 meters of the race, these are the split times for Bolt. For each distance, calculate the average velocity from the start to that distance, and the average velocity over the last 10 metres.
      Distance (m) Time (s) Average velocity

      since start (m/s)
      Average velocity

      previous 10m (m/s)
      0 0 – –
      10 1.50
      20 2.54
      30 3.47
      40 4.33
      50 5.17
    3. Why was Bolt’s average velocity the lowest for the first 10 meters?