A particle follows a path r 1 (t) on the helical curve with parametrization r() = (cos , sin , ). When it is at

A particle follows a path r₁(t) on the helical curve with parametrization r(θ) = (cos θ, sin θ, θ). When it is at position r(π/2), its speed is 3 m/s and it is accelerating at a rate of 1/2 m/s². Find its acceleration vector a at this moment. The particle’s acceleration vector does not coincide with r"(θ).