Question

The coefficient of static and kinetic frictions between a 3.0-kg box and a desk are 0.40 and 0.30, respectively. What is the net force on the box when a 14.3 N horizontal force is applied to the box?

Answer 1

net force on the box:

$F_{net}=F-\mu_kmg$

where $\mu_k$ is coefficient kinetic friction

$F_{net}=14.3-0.4\cdot3\cdot9.8=2.54$ N