Page 47 - CITS - ED - Mechanical
P. 47
ENGINEERING DRAWING - CITS
Similar to prisms, pyramids also are known by the shape of their base viz triangular, square, rectangular, pentag-
onal, hexagonal etc. The imaginary line joining the centre of the base to the apex is called the AXIS.
Fig 3 shows some pyramids and their views.
Fig 2 Fig 3
Solids of revolution: When a plane figure revolves about an axis a solid is generated.
Example
The solid shown in the Fig 4 is formed by the revolution is formed by the revolution of the plane (Fig 4A) abc about
the axis ab.
Geometrical solids like cylinder, cone and sphere are solids of revolutions.
Cylinder: When a rectangle rotates about one of its sides a cylinder is generated.
Cylinder has two flat circular faces and a curved surface. (Fig 4B)
Cone: When a right angled triangle revolves about one of its side forming the right angle, a cone is generated.
Cone forming has a circular face and a slant curve surface. (Fig 4c)
Sphere: When a semi-circle revolves about its diameter a sphere is generated. A sphere has no flat surface.
(Fig 4D)
Fig 4
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CITS : Engineering Drawing (Mechanical) - Exercise 4
