Question

pleease answer 2 questions please maths legend

Answer 1

Solution :

Given diameter of a lead ball( d ) = 2.1cm

radius ( r ) = d/2

= 2.1/2 cm

V = ( 4/3 )πr³

= (4/3)(22/7)(2.1/2)³

=( 101.87)/21 cm³

= 4.851 cm³

Weight of the ball = V × density

= 4.851 × 11.34

= 55.010 gm

_______________________

Diameter of the cylinder (d)= 5cm

radius (r)= d/2 = 5/2 = 2.5cm

Height of the cylinder (h) =3⅓=10/3cm

Volume of the cylinder (V) = πr²h

= π ×2.5×2.5×10/3

If cylinder melted and to make a

sphere .

Let radius of the sphere = R

volume of the sphere = volume of

the cylinder

(4/3)πR³ = π×2.5×2.5×10/3

=> R³ = ( π×2.5×2.5×10×3)/(3×π×4)

=> R³ = 2.5×2.5×2.5

=> R³ = (2.5)³

=> R = 2.5 cm

Therefore ,

diameter of the sphere (d) = 2R

= 2.5 × 2 = 5 cm

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