Question

The perception- reaction time for a vehicle travelling at 90 km/h, given the coefficient of longitudinal friction of 0.35 and the stopping sight distance of 170 m (assume g = $9.81m/s^2$, is_______seconds

• A. 3.15

Answer 1

The correct option is A 3.15
$\text{SSD}=0.278v{t}_r+\frac{(0.278\times 90{)}^2}{2gf}$

$\Rightarrow 170=0.278\times 90\times t_r+\frac{(0.278\times 90{)}^2}{2\times 9.81\times 0.35}$

$\Rightarrow t_r=3.1510sec$