Ta có: \(A = 10cm = 0,1m\)
a) \({\rm{W}} = {W_{{t_{\max }}}} = \dfrac{1}{2}k{A^2}\)
\( \Rightarrow k = \dfrac{{2W}}{{{A^2}}} = \dfrac{{2.1}}{{0,{1^2}}} = 200(N/m)\)
b)\({\rm{W}} = {{\rm{W}}_{{d_{\max }}}} = \dfrac{1}{2}mv_{\max }^2\)
\( \Rightarrow m = \dfrac{{2W}}{{v_{\max }^2}} = \dfrac{{2.1}}{{1,{2^2}}} = 1,39(kg)\)
c) Tần số dao động: \(f = \dfrac{1}{{2\pi }}\sqrt {\dfrac{k}{m}} = \dfrac{1}{{2\pi }}\sqrt {\dfrac{{200}}{{1,39}}} = 1,9(Hz)\)
