Question 107
Metallic discs of radius 0.75 cm and thickness 0.2 cm are melted to obtain 508.68 cm3 of metal. Find the number of disc melted. (Use π=3.14)
Radius of metallic disc = 0.75 cm
Thickness of disc = 0.2 cm
Total volume of material which will be used in forming/melting of disc =508.68 cm3
∴ Material required for one disc = Volume of cylinder.
=πr2h=227×0.75×0.75×0.2 [∵ shape of a disc is a cylinder]
=3.14×0.75×0.75×0.2
=0.35325 cm3.
Number of discs can be melted =Total volume of metal obtained after meltingVolume of one disc
=508.680.35325=1440 discs