Question

A sphere of radius 10.0cm is moulded into a uniform cylindrical wire of radius r calculate length of the wire

Answer 1

When the sphere is moulded into a uniform cylindrical wire volume of the material remains constant

Volume of the sphere =$\dfrac{4}{3}\pi r'^3$

Volume of cylinder = $\pi r^2h$

$\to \pi r^2h= \dfrac{4}{3}\pi (r')^3$

$\to r^2h=(4/3)*1000$

$\to h= (4/3)*\dfrac{1000}{r^2}$ length of the wire