\[\boxed{\mathbf{911.ОК\ ГДЗ - домашка\ на}\ 5}\]
\[\overrightarrow{h} = k\overrightarrow{h}\]
\[\textbf{а)}\ 2 = |k| \bullet 0,5 \Longrightarrow |k| = 4;\]
\[\overrightarrow{m}\ \uparrow \downarrow \ \overrightarrow{h} \Longrightarrow k < 0 \Longrightarrow k = - 4.\]
\[\textbf{б)}\ 240 = |k| \bullet 12 \Longrightarrow |k| = 20;\]
\[\overrightarrow{m}\ \uparrow \uparrow \ \overrightarrow{h} \Longrightarrow k > 0 \Longrightarrow k = 20.\]
\[\textbf{а)}\ 400 = |k| \bullet 400 \Longrightarrow |k| = 1;\]
\[\overrightarrow{m}\ \uparrow \downarrow \ \overrightarrow{h} \Longrightarrow k < 0 \Longrightarrow k = - 1.\]
\[\textbf{а)}\ \sqrt{50} = |k| \bullet \sqrt{2} \Longrightarrow |k| =\]
\[= \sqrt{25} = 5;\]
\[\overrightarrow{m}\ \uparrow \uparrow \ \overrightarrow{h} \Longrightarrow k > 0 \Longrightarrow k = 5.\]