Question -
Answer -
Given,
Diameter of the solidcylinder = 2 cm
Length of hollowcylinder = 16 cm
The solid cylinder isrecast into a hollow cylinder of length 16 cm, external diameter of 20 cm andthickness of 2.5 mm = 0.25 cm
We know that,
Volume of a cylinder =πr2h
Radius of the solidcylinder = 1 cm
So,
Volume of the solidcylinder = π12h = πh cm3
Let’s assume thelength of the solid cylinder as h
And,
Volume of the hollowcylinder = πh(R2– r2)
Thickness of thecylinder = (R – r)
0.25 = 10 – r
So, the internalradius of the cylinder is 9.75 cm
Volume of the hollowcylinder = π × 16 (100 – 95.0625)
Hence, it’s understoodthat
Volume of the solidcylinder = volume of the hollow cylinder
πh = π × 16(100 –95.06)
h = 79.04 cm
Therefore, the lengthof the solid cylinder is 79.04 cm.