A block of mass 10 kg is placed on the horizontal surface of a flatbed truck. The coefficient of static friction between the block and the surface is 0.5 , and the coefficient of kinetic friction is 0.4 . If the truck accelerates forward at 3 m s ⁻² , what is the magnitude of the frictional force acting on the block? (Take g = 10 m s ⁻² )

Step-by-step solution

The limiting static friction force is given by: f_ s, max = _s mg f_ s, max = 0.5 10 10 = 50 N The force required to accelerate the block along with the truck is: F_ req = ma = 10 3 = 30 N Since the required force ( 30 N) is less than the limiting static friction ( 50 N), the block does not slip relative to the truck. Static friction is self-adjusting and will exactly match the required force to keep the block at rest relative to the truck. Therefore, the actual frictional force acting on the block is 30 N. Answer: