\[s(t) = 1 - t + t^{2};m = 5\ кг.\]
\[1)\ \ t = 10\ с:\]
\[s^{'}(t) = - 1 + 2t;\]
\[s^{'}(10) = - 1 + 2 \bullet 10 = 19.\]
\[2)\ t = 10\ с:\]
\[E = \frac{mv^{2}}{2} = \frac{5 \bullet 19^{2}}{2} =\]
\[= \frac{5 \bullet 361}{2} = 902,5\ Дж.\]
\[Ответ:\ \ 902,5\ Дж.\]