JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech I Year ENGINEERING GRAPHICS Previous Question Paper (January/February - 2024 - R16)
Answer any five questions. All questions carry equal marks.
Main
Construct an ellipse when the distance of the focus from the directrix is equal to 50 mm and eccentricity is 2/3.
Answer
To construct an ellipse with a focus-directrix distance (VF) of 50 mm and eccentricity (e) of 2/3, follow these steps:
- Draw a vertical line as the directrix and a horizontal line passing through it as the axis.
- Mark the intersection point as V. Locate the focus F on the axis at a distance of 50 mm from V.
- Divide the line segment VF into (2+3) = 5 equal parts. Since e = 2/3, mark the vertex A at the second division from V. Thus, VA = 20 mm and AF = 30 mm.
- At vertex A, draw a perpendicular line to the axis. Measure a distance equal to AF (30 mm) on this perpendicular line to locate point B.
- Draw a line passing through the origin (the intersection of the directrix and axis) and point B, extending it further.
- Mark several points 1, 2, 3, etc., on the axis beyond A. Draw vertical lines through these points intersecting the line passing through the origin at 1', 2', 3', etc.
- With F as the center and radius equal to the distance 1-1', draw arcs intersecting the vertical line passing through point 1 at P1 and P1'. Repeat this process for points 2, 3, etc.
- Join all the points (P1, P2, P3, etc.) with a smooth curve to complete the ellipse.
On a map, the distance between two points is 14 cm. The real distance between them is 20 km. Draw a diagonal scale of this map to read kilometres and hectametres, and to measure upto 25 km. Show a distance of 17.6 km on this scale.
Answer
To construct the diagonal scale, first calculate the Representative Fraction (RF). Given that 14 cm represents 20 km, we have:
The Length of Scale (LOS) for a maximum length of 25 km is:
Construction steps:
- Draw a line 17.5 cm long and divide it into 25 equal parts, each representing 1 km. Label these 0, 1, 2, ..., 24.
- At the 0 mark, erect a vertical line and divide it into 10 equal parts. Each division represents 1 hectametre (0.1 km).
- Draw horizontal lines through these 10 divisions across the entire length of the scale.
- Draw diagonal lines connecting the 0 mark on the top horizontal line to the 1st division on the base line, the 1st division on the top to the 2nd on the base, and so on.
- To measure 17.6 km, place one end of the divider at the 17 km mark on the base line and the other end at the intersection of the 6th horizontal line and the diagonal line originating from the 17th division.
The top view of a 75 mm long line CD measures 50 mm. C is 50 mm in front of the V.P. and 15 mm below the H.P. D is 15 mm in front of the V.P. and is above the H.P. Draw the front view of CD and find its inclinations with the H.P. and the V.P.
Answer
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A semi-circular plate of 80 mm diameter has its straight edge in the V.P. and inclined at 45° to the H.P. The surface of the plate makes an angle of 30° with the V.P. Draw its projections.
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A pentagonal pyramid, base 25 mm side and axis 50 mm long has one of its triangular faces in the V.P. and the edge of the base contained by that face makes an angle of 30° with the H.P. Draw its projections.
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A tetrahedron of 75 mm long edges has one edge parallel to the H.P. and inclined at 45° to the V.P. while a face containing that edge is vertical. Draw its projections.
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A triangular pyramid, having base 40 mm side and axis 50 mm long, is lying on the H.P. on one of its faces, with the axis parallel to the V.P. A section parallel to the V.P. cuts the pyramid at a distance of 6 mm from the axis. Draw its sectional front view and the top view.
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A cone, base 65 mm diameter and axis 75 mm long, is lying on the H.P. on one of its generators with the axis parallel to the V.P. A section plane which is parallel to the V.P. cuts the cone 6 mm away from the axis. Draw the sectional front view and development of the surface of the remaining portion of the cone.
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The orthographic projections of the object is shown in the following figure 1. Draw the isometric view of the object. (All dimensions are in mm)
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Draw (a) Front view. (b) Both side views. (c) Top view of the following figure 2. (All dimensions are in mm)
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