Question

A cylindrical metal bar of diameter 14 cm and length 2m is melted and moulded into spherical balls.In the process,5% by volume is lost and what remains makes ball of radius 3.5cm.a)calculate the volume of metal used to make the balls.b)find to the nearest whole number the number of balls made.c)find the total surface area of the metal bar.find the total surface area of the balls made.Explain in detail.

Answer 1

volume of original bar is πr^2 h = 9800π cm^3
after melting, 95% remains, or 9310π cm^3
(a) volume of each ball is 4/3 πr^3 = 57.17π cm^3
(b) # balls n = volume/57.17π
(c) area = 4πr^2 * n

Answer 2

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