A uniform disk of radius \(R\) is mounted on a fixed axle through its center and is initially at rest. Beginning at time \(t = 0\), a constant net torque is applied to the disk, producing a constant angular acceleration \(\alpha\). A point \(P\) is located on the outer rim of the disk. Which of the following best describes the shapes of the graphs of the tangential acceleration \(a_t\) and centripetal acceleration \(a_c\) of point \(P\) as functions of time \(t\)?