Answer
Porsche will win the race
Work Step by Step
We have
Distance $s=400m$
Porsche's acceleration $a_p=3.5m/s^2$
Honda's acceleration $a_h=3.0m/s^2$
Since both start from rest their intial velocities are zero.
Time taken by Porsche is given by
$ s=ut+\frac{1}{2}a_pt^2$
$400 = 0 + \frac{1}{2}(3.5)*t^2$
$t^2 = 228.6 s^2$
$t = 15.12 s$
Now Time taken by Honda is given as
$ s=ut+\frac{1}{2}a_ht^2$
$400 = 0 + \frac{1}{2}(3.0)*t^2$
$t^2 =266.67s^2$
$t=16.33s$
since Honda was given 1.0 s head start. Therefore time taken by Honda $=16.33-1 =15.33 s$
As time taken by Honda is greater than time taken by Porsche.
Thus Porsche will win the race.
