Question

A piece of metal pipe is 77cm long and the inside diameter of a cross section is 4cm and the outside diameter is 4.5m if the metal weighs 8g per cu.cm what is the weight of the piece of pipe

Answer 1

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

Answer 2

Answer:

Step-by-step explanation:

Given :-

Height of metal pipe, h= 77 cm

Inner radius of metal pipe, r = 4/2 cm = 2 cm

Outer radius of metal pipe, R = 4.5/2 cm = 2.25 cm

Weight per cubic cm = 8 g

To Find :-

The weight of the piece of pipe

Formula to be used :-

Volume of the pipe = πR²h - πr²h

Solution :-

Putting all the values, we get

Volume of the pipe = πR²h - πr²h

Volume of the pipe = πh(R+r)(R-r)

Volume of the pipe = 22/7 × 77 × (2.25-2) (2.25+2)

Volume of the pipe = 257.02 cm³

Weight of 257.02 cubic cm = 257.02 x 8 g

= 2056.16 g

= 2.05 kg

Hence, the weight of the piece of pipe 2.05 kg.