1. The problem statement, all variables and given/known data Block A weighs 75lbf and the coefficients of static and kinematic friction between A and the plane are both 0.50. Determine the acceleration of A under the action of the 25 lbf force when the velocity at A is (a) 8fps up the plane, (b) 15 fps down the plane. (c) Zero. 2. Relevant equations Sum of all forces = mass * acceleration 3. The attempt at a solution I dont know where to start... the box is doing up a plane and it's cosine is 4/5 and its sine is 3/5.