Đáp án:

\(\begin{array}{l}
a.W = 0,5J\\
b.v = 1m/s\\
c.v = 0,866m/s\\
d.\Delta l = 6cm
\end{array}\)

Giải thích các bước giải:

\(\begin{array}{l}
a.\\
W = {W_{t\max }} = \frac{1}{2}k\Delta {l^2} = \frac{1}{2}.100.0,{1^2} = 0,5J\\
b.\\
{W_{d\max }} = W\\
\frac{1}{2}m{v^2} = 0,5\\
\frac{1}{2}.1.{v^2} = 0,5\\
 \Rightarrow v = 1m/s\\
c.\\
{W_d} = W - {W_t}\\
\frac{1}{2}m{v^2} = 0,5 - \frac{1}{2}k\Delta {l^2}\\
\frac{1}{2}.1.{v^2} = 0,5 - \frac{1}{2}.100.0,{05^2}\\
 \Rightarrow v = 0,866m/s\\
d.\\
80cm/s = 0,8m/s\\
{W_t} = W - {W_d}\\
\frac{1}{2}k\Delta {l^2} = 0,5 - \frac{1}{2}m{v^2}\\
\frac{1}{2}.100\Delta {l^2} = 0,5 - \frac{1}{2}.1.0,{8^2}\\
\Delta l = 0,06m = 6cm
\end{array}\)