Đáp án:
\(\begin{array}{l}
23.\\
a.\\
v = 1,782m/s\\
b.\\
v = 2,42m/s\\
24.\\
a.\\
v = 1,711m/s\\
T = 15,98N\\
b.\\
v = 2m/s\\
T = 20N
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
23.\\
a.\\
v = \sqrt {2gl(\cos \alpha - \cos {\alpha _0})} = \sqrt {2.10.1(\cos 30 - \cos 45)} = 1,782m/s\\
b.\\
v = \sqrt {2gl(\cos \alpha - \cos {\alpha _0})} = \sqrt {2.10.1(\cos 0 - \cos 45)} = 2,42m/s\\
24.\\
a.\\
v = \sqrt {2gl(\cos \alpha - \cos {\alpha _0})} = \sqrt {2.0,4.10(\cos 30 - \cos 60)} = 1,711m/s\\
T = mg(3\cos \alpha - 2cos{\alpha _0}) = 1.10(3\cos 30 - 2\cos 60) = 15,98N\\
b.\\
v = \sqrt {2gl(\cos \alpha - \cos {\alpha _0})} = \sqrt {2.10.0,4(\cos 0 - \cos 45)} = 2m/s\\
T = mg(3\cos \alpha - 2cos{\alpha _0}) = 1.10(3\cos 0 - 2\cos 60) = 20N
\end{array}\)