A spring of negligible mass stretches 2.20 cm from its relaxed length when a force of 10.5 N is applied. A 1.1 kg particle rests on a frictionless horizontal surface and is attached to the free end of the spring. The particle is displaced from the origin to x=5. cm and released from rest at t=0.

(g2) Determine the acceleration of the particle when t=0.50 s