SOLUTION: A solid aluminium casting for a pulley consist of three discs, each 3/2 thick, of diameter 4cm, 6cm and 8cm. A central hole 2cm in diameter is drilled out. If the density of alumin

(1)  Consider the disk of the diameter 4 cm.


     Calculate its volume  =  cubic centimeters.


     Similarly, calculate the volume of the central hole of 2 cm in diameter.


     From , subtract the volume of the central hole, You will obtain the volume  of the solid metal.



(2)  Do the same for two other disks and find the solid metal volumes    and    for that disks.



(3)  Add  ,    and   to get the total solid metal volume.



(4)  Multiply the total solid metal volume by the density to get the mass of the pulley.