Question

A girl running in a race accelerates at $2.5m/s^2$ for the $4seconds$ of the race. How far does she travel in this time?

Answer 1

Step 1 : Given data

Acceleration of the girl, $a=2.5m/s^2$
Time of Acceleration , $t=4seconds.$
Initial velocity , $u=0m/s.$
Step 2: using second equation of motion

Distance covered, $s=u\times t+\frac{1}{2}\times a\times t^2$

Step 3: calculating the distance travelled by her.
$s=0\times 4+\frac{1}{2}\times 2.5\times 4^2$
$s=2.5\times 8=20metre$
Hence, the girl travels $20metre$ in this time.