Question

A girl running a race accelerates at 2.5m/s2 from the first 4 seconds of race. How far does she travel in this

Answer 1

We have,
distance (s) = ?
Time = (t) = 4 seconds
Acceleration (a) = 2.5m/s²
Initial velocity (u) = 0 (the girl started the race)
So, by using second equation of motion we have,
s = ut + $\frac{1}{2}$at²
s = 0*4 + $\frac{1}{2}*2.5*4*4$
s = 0 + 20
s = 20
So, the distance travelled by the girl is 20 m.


 

Answer 2

From second equation of motion,
S=ut+1/2at^2
S=0*4+1/2*2.5*4^2
S=1/2*2.5*16
S=2.5*8
S=20 m