Question

An athlete, initially at rest, takes $2 \, s$ to reach his maximum speed of $36 \, km \, h^{- 1}$ . The magnitude of his average acceleration (in $m \, s^{-2}$ ) is

Answer 1

The final speed of the athlete, $v=36 \, km \, h^{- 1}=36\times \frac{5}{18}=10 \, m \, s^{- 1}$
initial speed, $u=0$
time taken $t=2 \, s$
for average acceleration, $a$
$v=u+at$
$a=\frac{v - u}{t}=\frac{10 - 0}{2}=5 \, m \, s^{- 2}$