Question

Jorge pushes a 10 kg box of medicine along a rough surface with 35N of force. He observes that it is only accelerating at a rate of 2 m/s2. What must the value of the force of friction be? (Assume the only two forces acting on the object are friction and Jorge).

 

Answer 1

$F-F_{fr}=ma, \implies$

$F_{fr}=F-ma,$

$F_{fr}=35-10\cdot 2=15~\text{N}.$