Practice question

**Energy in SHM** interconverts between kinetic K = ½ m v² = ½ m ω² (A² - x²) and potential U = ½ k x² = ½ m ω² x², total E = K + U = ½ k A² = ½ m ω² A² constant, independent of time. At mean position x=0, E = K_max = ½ m ω² A², at extremes x=±A, E = U_max = ½ k A². Total energy: E = (1/2) k A² . 0.9 = 0.5 × 180 × A² ⇒ 0.9 = 90 A² ⇒ A² = 0.01 ⇒ A = 0.1 m . Applying x = A