Q.

A vessel full of water is in the form of an inverted cone of height 8 cm and the radius of its top, which is open, is 5 cm. 100 spherical lead balls are dropped into the vessel. One fourth of the water flows out of the vessel. Find the radius of a spherical ball.


Ans.

(0.5)

Height (h) of the cone = 8 cm and radius (r) of the cone = 5 cm

 Volume of water flows out =14× volume of cone

=14×13πr2h=112×π×25×8

 Volume of water flows out = 100 × volume of spherical ball

112×π×25×8=100×43πR3

R3=18R=12cm=0.5cm