There is a 760N heavy car on a plane which is inclined to the horizontal at an angle of 6.8 degrees. Calculate the forward driving force which accelerates the car down the slope. I know the answer is 760sin6.8. I know that the forward driving force has a direction which is parallel to the slope.The thing I want to know is why the 760N vector is resolved in to its perpendicular component? We can have an infinite no. of pairs of components in which one of the component has a direction which is parallel to slope. why cant we resolve it like that: |*...... unknown vector parallel to the slope |......* |..........* |_________*. <-----------This angle is 6.8deg. unknown vector pointing towards left I hope that you guys understand what I am saying. Thanks in advance for any help.