Question

A vehicle was stopped in two seconds by fully jamming the breaks. The skid marks measured 9.8 meters. The average skid resistance coefficient will be

Answer 1

Initial speed of vehicle
v = fgt
$s=\frac{v^2}{2fg}=\frac{f^2{g}^2{t}^2}{2fg}$

$\therefore f=\frac{2s}{g{t}^2}=\frac{2\times 9.8}{9.8\times 2^2}=0.5$