m : 800 kg
F1 = 270 N
F2 = 480 N
Ff = 300 N
"miu" - coeficientul de frecare
Ff = miu × m × g
g = 10 N/kg
G = m × g = 800 kg × 10 N/kg = 8000 N
Ff = miu × G => miu = Ff / G = 300 N / 8000 N = 0,0375
F = F1 + F2 = 270 N + 480 N = 750 N
F = m × a => a = F/m = 750 N / 800 kg = 0,9375 m/s^2