Question

The difference between outside and inside surface of a cylindrical metallic tube 147 cm long is 184.8 cm². If 572.88 cm³ if a metal is used in the , find the outer and the inner radii of the tube.​

Answer 1

Step-by-step explanation:

ANSWER

Let, R be the external radius and r be the inner radius of the metallic pipe. h=14cm

Outer surface area−inner surface area=44cm

2

∴2πRh−2πrh=44cm

2

∴R−r=

2×

7

22

×14

44

=

2×22×14

44×7

∴R−r=

2

1

.

The volume of metal used =99cm

3

∴ External volume − internal volume =99cm

3

∴πR

2

h−πr

2

h=99cm

3

∴πh(R

2

−r

2

)=99cm

3

∴

7

22

×14(R+r)(R−r)=99cm

3

[∵a

2

−b

2

=(a+b)(a−b)] and [∵R−r=1

/2

]

Answer 2

Answer:

outer surface area -inner surface area

2πRh-2πrh

R-r=2×22×14

=44×14

=616cm^2