You have ALREADY done this experiment:
If there were no friction, what should the acceleration have been? What was the actual acceleration you measured?
Based on your measurements,
Fine. But ... is this correct?
One way to find out is to change the angle of the track and repeat the experiment. If friction really behaves as described in class and in your textbook, then NOW you should be able to predict the motion of the block accurately. Let's see if you can....
If you have time ... Repeat the experiment at this same angle of 23 degrees, making at least five trials. What sort of uncertainty should you attach to your measurement of acceleration? What sort of uncertainty should you attach to your measurement of coefficient of kinetic friction?