Page 88 - WCS - Electrical

WORKSHOP CALCULATION & SCIENCE - CITS

4 22
x x r³ = 15625
3 7
15625 x 3 x 7
r³ =
4 x 22
328125
=
88
= 3728.69
3
r = 3728.69
= 15.51 cm
diameter = 2 x radius

= 2 x 15.51
= 31.02 cm
3 How many spherical balls of 1 cm radius can be made from a sphere of 32 cm diameter.
No. of balls x volume of small sphere = Volume of bigger sphere
4 4 4
N x x r³ = r³
3 3 3
4 4 4
N x x x 1³ = x x r3
3 3 3
N = 16 x 16 x 16
= 4096 balls

4 Three brass balls of diameters 3 cm, 4 cm and 5 cm are melted and make into one solid ball, if there is no
wastage. Find the diameter of the solid ball.
1 ball d1 = 3 cm,
st
r1 = 1.5 cm
2 ball d2 = 4 cm,
nd
r2 = 2 cm
3 ball d3 = 5 cm,
rd
r1 = 2.5 cm
Diameter of new ball = ?

Volume of new ball = Volume of 3 spherical balls
4 4 4 4
r3 = r1³ + r2³ + r3³
3 3 3 3
4 4
r³ = (1.53 + 23 + 2.5)3
3 3
r³ = 3.375 + 8 + 15.625
r³ = 27

r =
3
r = 3x3x3

r = 3 cm

75

CITS : WCS - Electrical - Exercise 6