Đáp án:
\(\begin{array}{l}
a.\\
{v_C} = \sqrt {10} m/s\\
b.\\
{v_B} = 2,7m/s\\
c.\\
{T_A} = 10N\\
{T_B} = 31,96N\\
{T_C} = 40N
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a.\\
{v_C} = \sqrt {2gl(cos\alpha - cos{\alpha _0})} = \sqrt {2.10.1(cos0 - cos60)} = \sqrt {10} m/s\\
b.\\
{v_B} = \sqrt {2gl(cos\alpha - cos{\alpha _0})} = \sqrt {2.10.1(cos30 - cos60)} = 2,7m/s\\
c.\\
{T_A} = mg(3cos\alpha - 2cos{\alpha _0}) = 2.10(3cos60 - 2cos60) = 10N\\
{T_B} = mg(3cos\alpha - 2cos{\alpha _0}) = 2.10(3cos30 - 2cos60) = 31,96N\\
{T_C} = mg(3cos\alpha - 2cos{\alpha _0}) = 2.10(3cos0 - 2cos60) = 40N
\end{array}\)