Answer:
Step-by-step explanation:
F - UkFN = ma Note Friction opposes the motion thus subtract friction from the force. Uk is the coefficient of kinetic friction. FN is the normal force equal to mg since I assume it’s on a horizontal surface.
F - Ukmg = ma (Note mass does NOT cancel.)
20 N - 0.3 (4kg)*(9,8 m/s^2) = 4kg*(a