Question

Vă rog ajutați-mă, este urgent, dau coroane!​

Answer 1

$G=mg=>m=\frac{G}{g}=\frac{20}{10}=2 kg=>m=2 kg\\v=const=>a=0\\ \sum\vec{R}=0<=>\vec{F}+\vec{N}+\vec{F_f}+\vec{G}=0\\Ox:F-F_f=0=\\Oy:N-mg=0=>N=mg\\F_f=\mu N=\mu mg=0,2*10*2=4 N=>F_f=4 N\\F-F_f=0=>F=F_f=4 N=>F=4 N\\F'=2 F=2*4=8 N\\\sum\vec{R}=m\vec{a}<=>\vec{F'}+\vec{N}+\vec{F_f}+\vec{G}=m\vec{a}\\Ox:F'-F_f=ma\\Oy:N-mg=0\\F'-F_f=ma=>a=\frac{F'-F_f}{m}=\frac{8-4}{2}=2 m/s^2=>a=2m/s^2$