Answer:
The magnitude of the acceleration is 0.0847 m/s²
Step-by-step explanation:
Given:
Displacement equation for the spring:
x = 0.1*cos(1.26*t)
Acceleration is the second derivative of displacement w.r.t.
Thus,



When t = 0.8 sec,



The magnitude of the acceleration is 0.0847 m/s².