2. Relevant equations I used F=ma to calculate F and pythag theorem to calculate slope lengths 3. The attempt at a solution On the left hand side (angle 35) the slope length is 636m, on the right hand side (angle 25) the slope length is 365m. Now, in my notes I know that F=ma and since there is an angle inbetween, to calculate work done the formula is: Work done = (F)(Cos,theta)(Distance) so we should use cos35 and cos 25 but on the videos and mark scheme they use sin instead of cos?? Could someone explain why we use sin and not cos?