Question

A 7.0N force acts on a 1.5 kg mass to give it an acceleration of 4.0 m/s2, south. The force of friction, including direction, is

Answer 1

$F_{net}=ma\to 7-F_f=1.5\cdot4\to F_f=0$

Based on the condition of the problem $F_f=0$ . Answer