A solid disc with radius R is is spinning. An object exerts a force F at the edge of the disc to slow down the disc. The disc slows down to rest in 6 seconds. How long would the disc take to stop if:

a) the mass of the disc doubled 12 s

b) the radius of the disc doubled 12 s

c) the force doubled 3 s

d) You exert a force F on the outer edge of a solid disc of thickness d and radius R, which results in a certain angular acceleration. If instead you were to try to angularly accelerate (with the same angular acceleration) a solid disc made of the same material and with the same thickness, but with 3 times the radius, what force would be required (in terms of the force F exerted in the first situation)?