試題詳解

8. The displacement of an object oscillating on a spring is given by x(t) = x_mcos(wt +Φ). If the object is initially displaced in the negative x direction and given a negative initial velocity, then the phase constant Φ is between:
(A) 3π/2 and 2π radians
(B) π and 3π/2 radians
(C) π/2 and π radians
(D) 0 and π/2 radians
(E) none of the above (Φ= π).