Question

An Olympic athlete of mass 80kg competes in a 100m race. What is The best estimate of his mean kinetic energy during the race?
A 400J
B 4000J
C 40000J
D 400000J
can someone explain to me in getting the final answer?

Answer 1

hint:
let's suppose that the time needed to the athlete to cover 100 meters is \(10\) seconds, then the average speed, is:
\[\Large v = \frac{d}{t} = \frac{{100}}{{10}} = 10\quad m/\sec \]
so the kinetic energy of the athlete, is:
\[\Large KE = \frac{1}{2}m{v^2} = \frac{1}{2} \cdot 80 \cdot {10^2} = ...?joules\]