If you are asked to calculate the accleration due to gravity, is that not a trick question? We did an experiment similar to Galileo's (cart down a ramp and measure time, distance, acceleration, and at diferent inclinations)...but if asked to find the accleration due to gravity on the cart at each of the angles, isn't the answer still going to be 9.82 m/s^2? We don't have masses or other forces, plus the mass is not even relevant? So, is this a trick question?