A body executes S.H.M. of period 20 seconds. Its velocity is 5 cm s - 1 , 2 seconds after it has passed the mean position. Find the amplitude of the bob cos 36 ° = 0 . 809

Step-by-step solution

Here,   T = 20   s Also, when t = 2   s ,   v = 5   cm   s - 1 Now,   v = A ω cos ωt = A × 2 π T cos 2 π T t ∴ 5 = A × 2 π 2 0 cos 2 π 2 0 × 2 or A π 1 0 cos π 5 = 5 or   π A 1 0 cos  36° = 5 or π A 1 0 × 0 . 8 0 9 0 = 5 or A = 19 . 67   cm