Question

Care este raspunsul la antrebare?

Answer 1

Răspuns:

Varianta 3

Explicație:

x=6sin(2t+π/6) (cm) ⇒ A=6cm=6·10⁻²m; ω=2 rad/s; φ=π/6 rad

4=6sin(2t+π/6)

sin(2t+π/6)=2/3 ⇒ sin²(2t+π/6)=4/9 ⇒ cos²(2t+π/6)=1-4/9=5/9

m=50g=5·10⁻²kg

Ec=mv²/2=mA²ω²sin²(ωt+φ)/2=5·10⁻²·36·10⁻⁴·4·sin²(2t+π/6)/2=180·10⁻⁶·16/18=16·10⁻⁵ J

Ep=kx²/2=mA²ω²cos²(ωt+φ)/2=5·10⁻²·36·10⁻⁴·4·cos²(2t+π/6)/2=180·10⁻⁶·20/18=20·10⁻⁵ J

⇒ Varianta 3