Solution of task 11.3.12 from the collection of Kepe OE

Solution of task 11.3.12 from the collection of Kepe OE

11.3.12
The link O1A rotates according to the equation φ = 2t. On the rim of a disk of radius r = 0.5 m, the point M moves according to the law s = 2rt.
Determine the modulus of absolute acceleration of the point M at time t = 0.25π. (Answer 4)