A Horizontal Disk with a Radius of 10 Cm Rotates

Multiple Choice

A horizontal disk with a radius of 10 cm rotates about a vertical axis through its center. The disk starts from rest at t = 0 and has a constant angular acceleration of 2.1 rad/s². At what value of t will the radial and tangential components of the linear acceleration of a point on the rim of the disk be equal in magnitude?

A) 0.55 s
B) 0.63 s
C) 0.69 s
D) 0.59 s
E) 0.47 s