Đáp án:
3. a. F=844,6N
b.\(a = 0,3128m/{s^2},v = 3631,824m/s\)
4.
a. \(a = 0,6m/{s^2}\)
b. F=0,55N
Giải thích các bước giải:
\(\begin{array}{l}
3.\\
a.\\
F = k\frac{{Mm}}{{{h^2}}} = 6,{67.10^{ - 11}}\frac{{{{2700.6.10}^{24}}}}{{{{35768000}^2}}} = 844,6N\\
b.\\
{F_{ht}} = {F_{hd}} = ma\\
a = \frac{{{F_{hd}}}}{m} = \frac{{844,6}}{{2700}} = 0,3128m/{s^2}\\
a = \frac{{{v^2}}}{{(r + h)}}\\
v = \sqrt {a(r + h)} = \sqrt {0,3128.(35768000 + 6400000)} = 3631,824m/s\\
4.\\
a.\\
s = \frac{1}{2}a{t^2}\\
a = \frac{{2s}}{{{t^2}}} = \frac{{2.1,2}}{{{2^2}}} = 0,6m/{s^2}\\
b.\\
{{\vec F}_k} + {{\vec F}_{ms}} + \vec N + \vec P = m\vec a\\
{F_k} - {F_{ms}} = ma\\
{F_k} = ma + {F_{ms}} = ma + \mu mg = 0,25.0,6 + 0,16.0,25.10 = 0,55N
\end{array}\)