Calculate the Force of Friction (Ff) for a 5 kg aluminum block being pulled with constant velocity (uniform motion), up a steel plank that is at a 30 degree angle to the horizontal.

Net force acting on the block is zero because it is moving with constant velocity.

Therefore,

frictional force should be balanced by one component of weight of the block along the plane.

∴f = mgsin30° = 5*9.8*0.5 = 24.5 N.