Đáp án:
11,25m
Giải thích các bước giải:
\([\begin{array}{l}
1.W = \frac{1}{2}mv_0^2 + mgh = \frac{1}{2}.0,{5.5^2} + 0,5.10.10 = 56,25J\\
2.W = mg{h_{\max }} \Leftrightarrow 0,5.10.{h_{\max }} = 56,25\\
\Rightarrow {h_{\max }} = 11,25m\\
3.{W_t} = \frac{1}{2}{W_d} \Rightarrow 3{W_t} = W\\
\Leftrightarrow 3mgh = mg{h_{\max }}\\
\Leftrightarrow h = \frac{1}{3}{h_{\max }} = \frac{1}{3}.11,25 = 3,75m\\
{W_t} = \frac{1}{2}{W_d} \Rightarrow \frac{3}{2}{W_d} = W\\
\Leftrightarrow \frac{1}{2}.\frac{3}{2}m{v^2} = W\\
\Leftrightarrow \frac{1}{2}.\frac{3}{2}.0,5.{v^2} = 56,25\\
\Rightarrow v = 5\sqrt 6 m/s\\
4.{v_{\max }} = gt = g.\sqrt {\frac{{2{h_{\max }}}}{g}} = 10.\sqrt {\frac{{2.11,25}}{{10}}} = 15m/s\\
5.\Delta {W_d} = {F_c}.s\\
\Leftrightarrow \frac{1}{2}m(v_{\max }^2 - {v^2}) = {F_c}.s\\
\Leftrightarrow \frac{1}{2}.0,5({15^2} - 0) = {F_c}.0,06\\
\Rightarrow {F_c} = 937,5N
\end{array}\)