F) According to the image below, the block initially at rest, has 5.5 kg and there is friction between

the block and plane, static coefficient μs = μk = 1,2. With a slope of 30 degree and the applied F force

varies in the time according to F(t) = 1 + 2t (in Sl and for t > 0).

F1) Prove that before the force acts on the block, the block does not slip plan below.

F2) Calculate the instant the block begins to move.

F3) At some point the force ceases to act and the block ends up immobilize at a distance of d = 5.0

meters above the place where started the movement, along the plane. Calculate the work of all

forces in the movement described above.