We had lab but how do I find theta in this case? These are the values I did on my experiment: 

 

Cart's weight = 289.2 grams or 0.2892 kg

 

The "Step 6" acceleration that I calculated turns out to be: 0.846 m/s^2. 

Also from my previous calculations in the earlier parts of the lab, the theta from the hypotenuse between H and L is 8.75 deg. I'm assuming the question is asking for the theta with the g? 

So far, we assume that the value of g is the accepted value of 9.8 m/s/s. From the vector diagram shown in Figure 3, the acceleration of cart is the component of g along the direction of the ramp. Thus the acceleration measured in Step 6 can lead to the value of g using the relation: H g= 6 a sino gsine 0 Figure 3 How does the value of g obtained this way compared to the accepted value?