Explain Force Magnitude and Direction Practice Test

A $5.0,\text{kg}$ box is pushed to the right across a horizontal floor with $F_{\text{app}}=25,\text{N}$ (→). The coefficient of kinetic friction is $\mu_k=0.20$. Take $g=10,\text{m/s}^2$.

Based on the forces, what is the net horizontal force on the box (magnitude and direction)?

A $12,\text{kg}$ crate is pulled across a horizontal floor at constant velocity by a rope that exerts an applied force $F_{\text{app}}=60,\text{N}$ to the right (→). The forces on the crate are: weight $F_g$ downward (↓), normal force $F_N$ upward (↑), applied force $F_{\text{app}}$ to the right (→), and kinetic friction $F_f$ to the left (←).

What is the magnitude of the friction force $F_f$ on the crate?