3 A block of mass M-25 kg is attached to the cord wound on the drum of diameter 100 mm and it is allowed to fall under the action of gravity (see Figure B3). The drum is firmly attached to gear A, gears B and C form a compound. The moments of inertia of each shaft are l=1.0 kgm, I(B+c)=1.5 kgm and -0.75 kgm. The number of teeth on gears A, B, C and D are 160, 120, 180 and 90 respectively. Calculate: a) the distance between shafts A and D if the module of all the gears is 2 mm (5 marks)