Answer:
[tex]\mu=0.39[/tex]
Explanation:
From the question we are told that:
Angle [tex]\theta=28[/tex]
Acceleration [tex]a=1.25m/s^2[/tex]
Generally the equation for Frictional force is mathematically given by
[tex]F=\muN[/tex]
Where
[tex]N=mgcos \theta[/tex]
[tex]N=mgcos 28[/tex]
Since
Friction force is acting against move of box
Therefore
[tex]mgsin(28) - 1.25m = \mu mgcos(28)[/tex]
[tex]\mu=\frac{gsin(28) - 1.25}{gcos(28)}[/tex]
[tex]\mu=0.39[/tex]