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प्रश्न
The diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of the metal is 8.9 g per cm3?
`["Assume "pi=22/7]`
उत्तर
Radius (r) of metallic ball = `(4.2/2)cm` = 2.1 cm
Volume of metallic ball = `4/3pir^3`
= `[4/3xx22/7xx(2.1)^3]cm^3`
= 38.808 cm3
Density = `"Mass"/"Volume"`
Mass = Density × Volume
= (8.9 × 38.808) g
= 345.3912 g
Hence, the mass of the ball is 345.39 g (approximately).
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