I did Kinematics challenge with one class. The car going up a slope was accelerating at 2.5 ms*-2 over a distance of 55m. It takes off and landed after flying through air for 2.2s. I discovered that a number of students were confused over the acceleration up the slope and acceleration due to gravity. The direction of acceleration is up the slope (no need to specify x or y) as it is linear. After take off need to specify x and y because acceleration is only in the y direction (downwards) and all other quantities like s and u and v has both x and y components. If velocity is required one need to recombine the components using pythagoras theorem and tangent of angle formula.
