Why Are Parts B-D of My Torque Calculations Incorrect?

[VitaX]

Homework Statement

Homework Equations

Torque is equal to the derivative of angular momentum with respect to time

The Attempt at a Solution

I took the derivative of each function given in parts a - d and plugged in the value for t to get my answer for the torque. I don't quite understand why parts b - d are wrong. Since it says clockwise do I reverse my signs in my final answer? The green portions represent correct answers.

 

[tiny-tim]

Hi VitaX!

… Since it says clockwise do I reverse my signs in my final answer?

clockwise is negative, so yes, you do reverse the sign (from the start)