A bike is moving around a pole at a distance defined as r = 5t² + 7 from the pole. What is the magnitude of the centripetal acceleration at t = 3s, if the angular velocity is given to be 3 rad/s ?

156

Centripetal Acceleration : $a_c = r \omega^2$

At time t = 3 s, $r = 5*3^2 +7 = 52$

Thus, $a_c = 3 \text{ rad/s * } 52$

$a_c = 156$