Two spheres are cut from a certain uniform rock. One has radius 4.50 cm. The mass of the other is five times greater.
Find its radius.
Assuming density is the same for the two spheres since they were cut from the same rock,
Density of sphere 1 = m1 / [(4/3)*Pi*r1^3], where r1-radius of sphere 1, m1 -mass of sphere 1
Density of sphere 2 = m2 / [(4/3)*Pi*r2^3], where r2-radius of sphere 2, m2 -mass of sphere 2
Given that m2 = 5m1
Therefore, m1/[(4/3)*Pi*r1^3] = 5m1/ [(4/3)*Pi*r2^3]
=> 1/r1^3 = 5 / r2^3 => r2^3 = 5*r1^3 => r2^3 = 5*(4.5^3) => r2^3 = 455.625 => r2 = 7.69 cm
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