F = Fb + Qs + T
Qs/Q = cosα => Qs = Qcosα = mg*cos30° = 20N * √3/2 = 10√3N ≈ 17N (dla √3=1,7)
Qn/Q = sinα => Qn = Qsinα = mg*sin30° = 20N * 1/2 = 10N
s=at²/2 => a =2s/t²
F = m*a + Qcosα + fQsinα = m* 2s/t² + 17N + 0,2*10N = 2N + 17N + 2N = 21N
Pozdrawiam,
matteushq;)