Question

find the mass of metallic hollow cylindrical pipe 24 cm long with internal diameter 10 cm and made of 5 mm thick metal , if 1cm^3 of metal weighs 7.5g

Answer 1

volume of metallic cylinder=pi. {R^2-r^2}.h
R=5cm+0.5cm
=5.5cm
r=5cm
h=24cm
now
volume =pi. {(5.5)^2-(5)^2}24=22/7.(10.5)(0.5)24=396cm^3
now mass of metal =396x7.5=2970g

Answer 2

given,
1.height = 24 cm
2.internal diameter =10 cm
3.radius =1/2* internal diameter=5cm
4. thickness of the cylinder = R-r
=5-r
r=thickness of the cylinder +R
=0.5+5
5.volume of the pipe=πh(R2-r2)
=22/7*24(5.5*5.5-5*5)
=22/7*24(30.25-25)
=22/7*24*5.25
=22*0.75*24
=396
6.mass=volume of the pipe*7.5
=396*7.5
=2970gm
=2.97kg