A block of  mass 2Kg is kept on a rough horizontal surface. It is pulled by applying a horizontal force F μs=0.6 and μk=0.4i)  If F = 12 N, frictional force on the block is 7.84Nii)  If F = 10 N, frictional force on the block is 10 Niii)  If F = 7.84 N, frictional force on the block is zero