Find the mass of 200 steel spherical ball bearings, each of which has radius 0.7 cm, given that the density of steel is 7.95 g/cm³. (Mass = Volume × Density)

GIVEN : no. of steel balls “n” = 200

Radius of each ball “r” = 0.7cm

we take π =

Density of steel = 7.95 g/cm³

TO FIND : Mass of 200 balls = ?

PROCEDURE :

We know that, volume of sphere "V” = × π r³

Putting the values in the above formula, we get

V = × × (0.7)³

= × × 0.343

= 1.437cm³

This was the volume of one ball.

Now volume of 200 balls “V’ ” = n× V = 200 × 1.437cm³

V’ = 287.466 cm³

Now, it is given that, Density of steel = 7.95 g/cm³

So, mass of the balls = volume × density

Mass of 200 balls = volume of 200 balls × density

= 287.466 cm³ × 7.95 g/cm³

= 2285.46g

= 2.285 Kg

∴ Mass of 200 balls bearings is 2.285 Kg.