Áp dụng định luật ll Niu tơn: \(\overrightarrow{F}+\overrightarrow{N}+\overrightarrow{P}+\overrightarrow{F_{ms}}=m\cdot\overrightarrow{a}\)
\(\left\{{}\begin{matrix}Ox:F_1-F_{ms}=m\cdot a\\Oy:F_2+N=P\end{matrix}\right.\)
\(\left\{{}\begin{matrix}F_1=F\cdot cos\alpha=F\cdot cos30^o=\dfrac{F\sqrt{3}}{2}\left(N\right)\\F_2=F\cdot sin\alpha=F\cdot sin30^o=\dfrac{F}{2}\left(N\right)\\N=P-F_2=mg-F_2=20\cdot10-\dfrac{F}{2}=200-\dfrac{F}{2}\left(N\right)\\F_{ms}=\mu\cdot N=0,5\cdot\left(200-\dfrac{F}{2}\right)\left(N\right)\end{matrix}\right.\)
Vật trượt đều trên sàn nên \(a=0\).
\(\Rightarrow Ox:F_1-F_{ms}=m\cdot a\)
\(\Rightarrow\dfrac{F\sqrt{3}}{2}-0,5\cdot\left(200-\dfrac{F}{2}\right)=m\cdot a=0\)
\(\Rightarrow F\approx89,6N\)