as per FBD we can see that there are two forces opposite to our applied force F
1. Component of weight along the inclined plane [tex]mgsin\theta[/tex]
2. Friction force along the inclined plane [tex]F_f[/tex]
now in order to find the acceleration we will use Newton's II law
[tex]F_{net} = ma[/tex]
here we can say that net force is given by
[tex]F_{net} = F - mgsin\theta - F_f[/tex]
now we can find friction force by its formula
[tex]F_f = \muN[/tex]
here normal force is
[tex]N = mgcos\theta[/tex]
now we have
[tex]F_f = \mu mgcos\theta[/tex]
now net force is given by
[tex]F_{net} = F - mgsin\theta - \mu mg cos\theta[/tex]
now acceleration is given by
[tex]a = \frac{F - mgsin\theta - \mu mgcos\theta}{m}[/tex]
now we will plug in all values in above expression
[tex]a = \frac{100 - 4*9.8sin23 - 0.7 *4*9.8*cos23}{4}[/tex]
[tex]a = 14.85 m/s^2[