Question

Ajutor cu problema numărul 3

Answer 1

$v_1=60 km/h=16,66 m/s\\v=0\\\Vec{G}+\vec{N}+\vec{F_f}=m\vec{a}\\Ox:-F_f=ma\\Oy:N-mg=0=>N=mg\\F_f=\mu N=\mu mg\\-\mu mg=ma|:m=>a=-\mu g\\v^2=v_1^2+2ad<=>0^2=16,66^2+2a*35<=>70a=-277,77|:70=>a=-3,96 m/s^2\\a=-\mu g=>\mu=-\frac{a}{g}=- \frac{-3,96}{10}=0,396\\ F_f=\mu mg=0,396*10*1000=3960 N=>F_f=3960 N$