Peg P is driven by the fork link OA along the curved path described by r= (2)

Question:

Peg P is driven by the fork link OA along the curved path described by r= (2θ) ft. At the instant 0 = π/4 rad, the angular velocity and angular acceleration of the link are θ́ = 3 rad/s and θ̈ = 1 rad/s². Determine the magnitude of the peg's acceleration at this instant.