I'm stuck on two problems 1 is #8(please see the pdf file): I know I have to solve this equation with this: F=MA I calcualated F by taking the magnitude of Fx and Fy: Fx=390*cos(9)i+335*cos(-28) Fy=390*sin(9)i+335*sin(-28) I got F as 687.756 and the mass is given: 3819kg So I divided those and I got the answer as .180 but the comp. says it's wrong. The second problem is 12(please see the pdf file): I know I have to do this: F = m*g-m*a*cos(angle) (is it right?) (I calculated the acceleration and it is right) so F = 3.35*9.8-3.35*5.67*cos(27) and I got 26.06. What's wrong? with this? Thanks in advance for the help.