Answer
$\tau_{net} = -0.20~Nm$
Work Step by Step
We can find the magnitude and direction of the net torque on the disk.
We do this by multiplying the magnitude of the applied force, the distance from the center of the disk, and the angle measured counterclockwise between the distance from the center of the disk and the applied force.
$\tau_{net} = Fr\sin\phi$
$\tau_{net} = F_1~r_1\sin\phi_1 + F_2~r_2\sin\phi_2$
$\tau_{net} = (30~N)(.02~m)\sin(-90^{\circ})+(20~N)(.02~m)\sin(90^{\circ})$
$\tau_{net} = -0.20~Nm$
This means that the torque on the disk is $-.20~ Nm$ in the clockwise direction.
