JNTU
JNTU B.Tech I Year ENGINEERING DRAWING Previous Question Paper (August - 2018 - R15)
Answer any five questions
All questions carry equal marks
Main
An area of 144 sq. cm on a map represents an area of 36 sq. km on the field. Find the R.F of the scale for this map and draw a diagonal scale to show kilometers, hectometers and decameters and to measure up to 10 kilometers, indicate on the scale a distance of 7 kilometers, 5 hectometers and 6 decameters.
Answer
To find the Representative Fraction (R.F.), we first relate the area on the map to the area on the ground:
The scale ratio for area is the square of the R.F.:
Since the R.F. is approximately 1:158,114, we calculate the Length of Scale (L.O.S.) for a maximum distance of 10 km:
To construct the diagonal scale:
- Draw a line 6.32 cm long and divide it into 10 equal parts, each representing 1 km.
- Divide the first division into 10 equal parts to represent hectometers (1 km = 10 hm).
- Erect a perpendicular of suitable height and divide it into 10 equal parts to represent decameters (1 hm = 10 dam).
- Draw horizontal lines through the division points and diagonal lines to complete the grid.
- To indicate 7 km, 5 hm, and 6 dam, mark the point on the 7th km division, move 5 subdivisions along the hectometer scale, and move up 6 subdivisions along the diagonal to the 6th decameter horizontal line.
A circle of 60 mm diameter rolls on a horizontal line for half a revolution clockwise and then on a line inclined at 60° to the horizontal for another half Clockwise. Draw the curve traced by a point P on the circumference of the circle, taking the bottom most point on the rolling circle as generating point in the initial position.
Answer
The curve described is a cycloid generated by a circle rolling along two different paths. To construct this, follow these steps:
- Draw a horizontal line and mark the starting point P0. Draw the circle of diameter 60 mm (radius r = 30 mm) such that P0 is at the bottom. Divide the circle into 12 equal parts (30° each) and label them 1, 2, ..., 12 starting from the bottom point P0 in a clockwise direction.
- For the first half revolution (clockwise) on the horizontal line, the center of the circle moves to the right. The distance covered is half the circumference, πr ≈ 94.25 mm. Divide this distance into 6 equal parts.
- Project the horizontal lines from the circle divisions to intersect with the vertical lines dropped from the center positions C1, C2, ..., C6. Mark the points P1, P2, ..., P6 where the path of the point P intersects these arcs.
- At the end of the first half revolution, the circle is at the point where the horizontal line meets the inclined line (60°). The point P is now at the top of the circle.
- For the second half revolution, the circle rolls along the line inclined at 60°. The center of the circle now moves along a path parallel to the inclined line at a distance equal to the radius r.
- Continue the construction by rotating the circle's divisions relative to the new inclined path. Plot the remaining points P7 to P12 by drawing arcs from the new center positions C7 to C12 with radius r, intersecting the corresponding radial lines from the circle.
- Join all points P0 through P12 with a smooth, continuous curve using a French curve to obtain the required cycloidal path.
A line AB 100 mm long has its front view inclined at an angle of 45° to XY. The point A is in VP and 25 mm above H.P. The length of the front view is 60 mm. Draw the top view of the line and measure its length. Also find the inclination of the line AB to H.P and V.P.
Answer
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A semi circular plate of 80 mm diameter has its straight edge in the VP and inclined at 45° to the HP. The surface of the plate makes an angle of 30° with the VP. Draw its projections.
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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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A cylinder with base 40mm diameter and axis 58mm long rests with a point of its base circle on HP. Its axis is inclined at 45° to HP and parallel to VP. A section plane perpendicular to both the HP and VP bisects the axis of the cylinder. Draw its front, top and sectional side views.
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A cube of 50 mm edge is resting on H.P. with a vertical face inclined at 30° to the V.P. It is cut by a section plane parallel to the V.P. and 10 mm from the axis. Draw the sectional views of the solid. Also draw the lateral development of the solid after removing the front portion of the solid.
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A vertical cone, base 75 mm diameter and axis 110 mm long is penetrated by a horizontal cylinder of 50 mm diameter in such way that both the solids envelope an imaginary common sphere and their axes intersect each other. Draw the projections of the solids when their axes lie parallel to the V.P.
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A rectangular prism of base edges 60 mm × 40 mm and height 80 mm is resting on its broader rectangular face on the ground with the base parallel to the PP. The PP bisects the axis of the object. The station point is on the central line of the object 80 mm in front of the PP and 70 mm above the ground. Draw the perspective projection of the object.
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Draw the orthographic projections for the pictorial view shown in figure. (All dimensions are in mm.)
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