Đáp án:
\(\begin{array}{l}
a.\\
W = 30J\\
b.\\
{h_{\max }} = 6m\\
c.\\
{v_{\max }} = 10,954m/s\\
d.\\
+ {W_d} = 3{W_t}\\
h = 1,5m\\
+ {W_t} = 3{W_d}\\
h = 4,5m
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a.\\
W = mgh + \frac{1}{2}m{v^2} = 0,5.10.1 + \frac{1}{2}.0,{5.10^2} = 30J\\
b.\\
W = {W_{t\max }} = mg{h_{\max }}\\
30 = 0,5.10{h_{\max }}\\
{h_{\max }} = 6m\\
c.\\
W = {W_{d\max }} = \frac{1}{2}m{v_{\max }}^2\\
30 = \frac{1}{2}0,5{v_{\max }}^2\\
{v_{\max }} = 10,954m/s\\
d.\\
+ {W_d} = 3{W_t}\\
W = {W_d} + {W_t} = 3{W_t} + {W_t} = 4{W_t}\\
30 = 4mgh = 4.0,5.10.h\\
h = 1,5m\\
+ {W_t} = 3{W_d}\\
W = {W_d} + {W_t} = \frac{1}{3}{W_t} + {W_t} = \frac{4}{3}{W_t}\\
30 = 4mgh = \frac{4}{3}.0,5.10.h\\
h = 4,5m
\end{array}\)
