According to Newton's second law of motion, Fnet = m x a. From the given above,
Fnet = (10 kg) x (-2 m/s²) = -20 N
The force of friction, Ff, which is a negative force is the product of the normal force and the coefficient of friction,
Ff = 20 N = k x (10 kg x 9.8 m/s²)
The value of k from the equation is 0.204. Thus, the coefficient of friction is equal to 0.204.