Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech I Year ENGINEERING GRAPHICS Previous Question Paper (April - 2018 - R16)
Answer all five questions. All questions carry equal marks.
Main
The foci of an ellipse are 120 mm apart and the minor axis is 80 mm long. Determine the length of the major axis and draw by Oblong method. Draw a curve parallel to the ellipse and 25mm away from it.
Answer
Given that the distance between the foci (F1F2) is 120 mm and the minor axis (CD) is 80 mm, we first determine the major axis (AB). In an ellipse, the distance from the center to a focus is denoted by c, and the distance from the center to the end of the minor axis is b. Here, 2c = 120 mm (c = 60 mm) and 2b = 80 mm (b = 40 mm). The semi-major axis (a) is calculated using the relation a² = b² + c². Thus, a² = 40² + 60² = 1600 + 3600 = 5200, so a = √5200 ≈ 72.11 mm. The major axis length (2a) is approximately 144.22 mm.
To construct the ellipse by the Oblong method:
- Draw a rectangle of width 144.22 mm and height 80 mm. Divide the rectangle into four equal quadrants.
- Divide the semi-major axis (top horizontal side) and the vertical side of the top-right quadrant into the same number of equal parts (e.g., 5 parts).
- Label the points on the horizontal side 1, 2, 3, 4 starting from the center, and on the vertical side 1', 2', 3', 4' starting from the top.
- Connect the end of the minor axis (top point) to points 1, 2, 3, 4.
- Draw lines from the end of the major axis (left point) through points 1', 2', 3', 4' until they intersect the corresponding lines from the previous step.
- Mark the intersection points and repeat this process for all four quadrants to complete the ellipse.
To draw the parallel curve 25 mm away, mark points at a perpendicular distance of 25 mm from various locations along the perimeter of the ellipse and join these points with a smooth curve.
Construct a diagonal scale to read kilometers, hectometers and decameters and long enough to measure up to 6 kilometers. When a line of length l cm on the map represents a distance of 0.5 kilometers. Calculate the R.F and indicate a distance of 2.45 kilometers on the scale.
Answer
To construct the diagonal scale, we first determine the Representative Fraction (R.F). Given that 1 cm on the map represents 0.5 km in reality, we convert both to the same units:
The maximum length to be measured is 6 km. The Length of Scale (L.O.S) is calculated as:
Construction steps:
- Draw a rectangle of 12 cm length and a convenient height (e.g., 5 cm).
- Divide the 12 cm length into 6 equal parts, each representing 1 km. Label the divisions 0, 1, 2, 3, 4, 5.
- Divide the first division (0 to 1 km) into 10 equal parts along the top and bottom to represent hectometers (1 km = 10 hm).
- Divide the height of the scale into 10 equal horizontal divisions.
- Draw diagonal lines from the hectometer divisions on the top edge to the corresponding divisions on the bottom edge to represent decameters (1 hm = 10 dam).
- To indicate 2.45 km: Locate 2 km on the main scale, 4 hectometers on the sub-division, and move up to the 5th horizontal line to mark the 5th decameter division.
A line LM 70 mm long has its end ‘L’ 10 mm above H.P and 15 mm in front of V.P. Its top view and front view measures 60 mm and 40 mm respectively. Draw the projections of the line and determine its inclination with H.P and V.P.
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Draw the projections of a circle of 50 mm diameter resting in the H.P. on a point A on the circumference, its plane inclined at 45 degrees to the H.P and the diameter AS making 30 degrees angle with the V.P.
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A pentagonal pyramid, base 25 mm side and axis 50 mm long has one of triangular faces in the V.P. and the edge of the base contained by that face makes an angle of 30 degrees with the H.P. Draw its projections.
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Draw the projections of a cylinder, base 45 mm diameter and axis 50 mm long, when it is resting on the ground on a point on its base circle with the axis making an angle of 30 degrees with H.P. and 45 degrees with the V.P.
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A cone, diameter of the base 50 mm and axis 50 mm long is resting on its base on the H.P. It is cut by a section plane perpendicular to the H.P. and passing through the apex. Draw its front view, sectional top view and true shape of the section.
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A hexagonal prism of base 30 mm side is 65 mm stands on one of its rectangular faces parallel to V.P. A circular base of diameter 40 mm is drilled completely through the prism such that the axis of the hole is perpendicular to VP and bisects the axis of the prism. Draw the development of the lateral surface of the prism showing the shape of the holes formed on it.
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Draw the Isometric view of the machine parts shown below figure 1. All dimensions are in mm.
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Draw the following orthographic projections of the machine part shown below figure 2.
a) Front view b) Top view c) Side view. All dimensions are in mm.
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