Question

[Nguyễn Mỹ Linh]

1) PT van toc cua 1 vat dao dong dieu hoa co dang v = Vcos(ωt + φ ). PT gia toc cua vat la:

A. a = ωVcos(ωt + φ)          B. a = ωVSin(ωt + φ)

C. a = -ωVcos(ωt + φ)         D. a = -ωVSin(ωt + φ)

Answer 1

[nguyễn thị hương giang]

\(V=\omega A;v=V\cdot cos\left(\omega t+\varphi\right)\)

\(\Rightarrow v=\omega Acos\left(\omega t+\varphi+\dfrac{\pi}{2}\right)\)

\(\Rightarrow a=v'=-\omega^2A\cdot cos\left(\omega t+\varphi\right)=-\omega V\cdot cos\left(\omega t+\varphi\right)\)

Chọn C.