Question

A well of 2m diameter is dug 14 m deep on the ground. Find the volume of earth taken out.

Answer 1

Answer

Well is a cylinder of Depth,L

′

=14m and radius R=1m

Embankment is a hollow cyllinder with inner and outer radii :R

i

=1m R

e

=? Height,L=0.4m

Width of embankment =R

e

−R

i

π(R

e

2

−R

i

2

)L=πR

2

L

′

R

e

2

=

L

R

2

L

′

+R

i

2

=35+1=36

⇒R

e

=6m

Hence width of embankment =5m

.

.

.

Warm regards:Miss Chikchiki

Answer 2

Let us assume well as a solid circular cylinder

Since well is spread evenly to form embankment so their volumes will be same so equating