Question

A piece of metal pipe is 77cm long with inside diameter of the section has 4 cm if the outer diameter is 4.5 CM and the metal weights 8 gram per centimetre cube then the weight of the pipe is
A. 2.057kg
B. 20.57 kg
C. 205.7 kg
D. None

Answer 1

Answer:

Given, outer diameter of the pipe =4.5cm and inner diameter =4cm

Therefore, outer radius (R) of the pipe =2.25cm and inner radius (r)=2cm

Given, length or height of the cylinder =77cm

So, volume of the cylinder =π(R

2

−r

2

)h=

7

22

×(2.25

2

−2

2

)77=257.125cm

3

Now, weight of the pipe = volume X density =257.125×8g=2057g =2.057kg

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Answer 2

Answer:

2056.16 g = 2.05 kg

Step-by-step explanation:

for a hollow cylindrical metal pipe,

height = h= 77cm

inner radius = r = 4/2 cm = 2cm

outer radius = R = 4.5/2 cm = 2.25cm

volume of the pipe = πR²h -πr²h

= πh(R+r)(R-r)

= 22/7  * 77 * (2.25-2) (2.25+2)

= 257.02 cm³

weight per cu.cm = 8g

weight of 257.02 cu.cm

= 257.02 x 8 g

= 2056.16 g

= 2.05 kg