A shot-putt is a metallic sphere of radius `4.9 cm.` If the density of the metal is `7.8 g` `" per "` `cm^3` , find the mass of the shot-putt

Explanation

A shot-put is a solid sphere of metal and its mass is equal to the product of its volume and density
Volume of the shot-put
`= (4)/(3)pi r^(3)`
`= ((4)/(3) xx (22)/(7) xx (49)/(10) xx (49)/(10) xx (49)/(10)) cm^(3)`
`= (1479016)/(3000) cm^(3) = 493 cm^(3)` (nearly)
Mass of `1 cm^(3)` of the shot-put = 7.8g
Mass of the shot-put
`= (7.8 xx 493)g`
`= ((78)/(10) xx (493)/(1000)) kg = (38454)/(10000) kg = 3.85kg` (nearly)
Hence, the mass of the given shot-put is `3.85 kg.`