1. If it inclines downward, the oblique component of gravity will form the driving force, that is, F+mgsin=ma, and the F-a diagram has negative intercept;

If it inclines upward, the oblique component of gravity will form resistance, that is, F-mgsin=ma, and F-a diagram has positive intercept;

2.s=0.5(v 1+v2)t, and the solution is v2=2s/t-v 1, that is, the intercept is the initial velocity and the gradient is 2/t, then a can be obtained by using v2=v 1+at.