The rear side of a truck is open and a box of mass 20kg is placed on the truck 4 meters away from the open end coofficent of friction between truck and block is 0.15 the truck starts from rest with an acceleration of `2m//sec^(2)`on a straight road The box will fall off the truck when truck is at a distance from the starting point equal to`(g=10m//s^(2))`