A truck moving at 100 km /h carries a steel girder that rest on its wooden floor. what is the minimum time in which the truck can come to a stop without the girder moving forward ? The coefficient of static friction between steel and wood is 0.5.

Answer 1

vf=vi+at
t= vi/a= vi/(force/mass)=-vi*mass/mass*mu= vi/mu=change km/hr to m/s, and you have it.