Answer:
Step-by-step explanation:
Fgrav = 45.9 N; Fnorm = 45.9 N; Ffrict = 5.32 N; Fnet = 3.81 N, right; mu = 0.116
The starting point for any problem such as this is the construction of a free-body diagram in which you show all the individual forces which are acting upon the book. There are two vertical forces - gravity and normal force. There are two horizontal forces - friction and the applied force.
Since there is no vertical acceleration, normal force = gravity force. Each of these forces can be determined using the equation Fgrav = m • g = (4.68 kg) • (9.8 m/s/s) = 45.864 N
The net force can be determined from knowledge of the mass and acceleration of the sled. Fnet = m • a = (4.68 kg) • (0.815 m/s/s) = 3.8142 N, right.
Since the net force is to the right (in the direction of the applied force), then the applied force must be greater than the friction force. The friction force can be determined using an understanding of net force as the vector sum of all the forces. So 3.81 N, right = 9.13 N, right + Ffrict. Therefore, Ffrict = 5.32 N, left.
The coefficient of friction can now be determined as the ratio of friction force to normal force. "mu" = Ffrict / Fnorm = (5.32 N) / (45.864 N) = 0.116.