The amplitude of a damped oscillator decreases to 0.9 times its original magnitude in 5s. In another 10s it will decrease to α times its original magnitude, where α equals?
0.81
0.729
0.7
0.6
Solution:
A=A0e⁻ᵏᵗ ⇒0.9A0=A0e⁻⁵ᵏ and αA0=A0e⁻¹⁵ᵏ solving ⇒α=0.729