A circular blade on a radial arm saw is turning at 257 rad/s at the instant the motor is turned off. In 17.0 s the speed of the blade is reduced to 90 rad/s. Assume the blade to be a uniform solid disk of radius 0.170 m and mass 0.400 kg. Find the net torque applied to the blade

Question

A circular blade on a radial arm saw is turning at 257 rad/s at the instant the motor is turned off. In 17.0 s the speed of the blade is reduced to 90 rad/s. Assume the blade to be a uniform solid disk of radius 0.170 m and mass 0.400 kg. Find the net torque applied to the blade 
We found the change in velocity over time and then multiplied by inertia of a disc. The answer we found was 0.05678. This was incorrect, any suggestions?

acceleration is in fact deltaV/time. The moment of inertia is...http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/RotationalKinematics/MomentInertia.html

I get The same answer you got, torque is in N-m

Thanks Mr. Pursley. We were correct except the answer was negative.