Khi tha tay he vat chuyen dong ve vi tri can bang voi $w_{1}=\sqrt{\frac{k}{m_{1}+m_{2}}}=10$
Khi do thoi gian de chuyen dong ve vi tri cb la
$t_{1}=\frac{T}{4}=\frac{\pi }{20}$
Khi den vi tri cb thi 2 vat co van toc v va theo bao toan nang luong co
$\frac{1}{2}kA^{2}=\mu mg.A+\frac{1}{2}mv^{2}$
$<=>v=0,3\sqrt{10}m/s$
Khi den vi tri cb hai vat tach nhau ra va m2 chuyen dong cham dan deu vs gia toc:
$a=\frac{F_{ms}}{m}=\mu g=0,5$
Thoi gian ma vat m2 di tu vi tri cb den khi dung lai la
$t_{2}=\frac{v}{a}=0,6\sqrt{10}$
Thoi gian can tinh la
$t=t_{1}+t_{2}\approx 2,06s$
Dap an D