Question

Giúp mik câu 34 vs ạ.

Answer 1

Câu 34:

\(u_0=acos\left(\omega t+\dfrac{\pi}{2}\right)\left(cm\right)\)

Tại \(t=\dfrac{\pi}{\omega}\Rightarrow u_M=acos\left(\omega.\dfrac{\pi}{\omega}+\dfrac{\pi}{2}-\dfrac{\pi}{2}\right)\Leftrightarrow-2=acos\left(\pi\right)\)

\(\Leftrightarrow-2=a\left(-1\right)\Leftrightarrow a=2\left(cm\right)\)

\(\Rightarrow\) Chọn C