# The mass of a steel ball of radius r is 30g. What is the mass of a steel ball of radius 2r?

January 12, 2021 | education

| Initial data: m1 (mass of a ball with radius r) = 30 g.

The formula for calculating the volume of the ball: V = 4/3 * Π * R ^ 3, therefore, with an increase in the radius of the ball by 2 times, its volume will increase by 2 ^ 3 = 8 times (V2 = 8V1).

Mass of a steel ball of radius 2r: m2 = ρ * V2 = ρ * 8V1 = 8m1 = 8 * 30 = 240 g.

Answer: The mass of a steel ball with a radius of 2r will be 240 grams.

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