The net force on an object subject to friction is equal to the sum of the applied force and the frictional force.
Mathematically,
[tex]F_{N} = ma = F_{applied} - f_{fr}[/tex]
Here, m is mass of object and a is its acceleration. We take frictional force negative because it opposes the motion of object.
Given, [tex]m=15\ kg[/tex] , [tex]F_{applied} =45\ N[/tex] and [tex]f_{fr} = 30\ N[/tex]
Substituting these values in above formula, we get
[tex]15\ kg\times a = 45\ N -30\ N=15\ N \\\\a=\frac{15\ N}{15\ kg} =1\ m/s^2[/tex].
Thus, the acceleration of an object is [tex]1\ m/s^2.[/tex]
