A box of mass 11.7 kg rests on the flat bed of a truck, the box is not tied down in any way. The coefficients of friction between the box and the flat bed are $\mu_s = 0.19$ and $\mu_k = 0.16$. The truck stops at a stop sign and then starts to move to the West with a carelessly large acceleration of 2.15 m/s²
Part A
While the truck is accelerating westward at 2.15 m/s², what is the East-West component of the force of friction on the box by the flat bed of the truck? Let East be positive.