This problem is keeping me up all night, I did what I thought was right to figure out the force needed but the answer sheet tells me that my solution is wrong, spend 4 hours trying to figure out what I did wrong can't come up with anything: A 280kg box slides 4.3m down a 30 degree incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. The effective coefficient of kinetic friction is 0.4. Calculate the force exerted by the man. It might well be that I am completely out of my mind today and forgetting some basic thing that I am supposed to do, anyways I tried to do: Ff = 280 * 9.8 * sin30 * 0.4 I am quite sure actually that I am forgetting something..... just god damn don't know what it is. thnx for any help in advance.