Answer:
Step-by-step explanation:
T = 8 s
angular frequency ω = 2π / T
= 2 π / 8
= π / 4
x ( t ) = A ( sinωt + π / 2 ) because initial phase difference is π / 2
= A cos ωt
= A cos π t / 4
v = Aω sinωt
= 2 x π / 4 sinωt
= .5 π sinπt / 4
when t = 2
v = .5 π sinπ x 2 / 4
= .5 π x 1
= 1.57 cm /s
At t = 3 s
v = .5 π sin π x 3 / 4
= .5 π sin 135°
= .5 π / √ 2
= 1.11 cm /s