OER- Engineering Drawing Topic: Introduction to Conic Sections IITBombayX: FDP201x Pedagogy for Online and Blended Teaching-Learning Process OER- Engineering Drawing (Mechanical & Allied) Topic: Introduction to Conic Sections Team Details: Prof. Sunil Pipleya (Team Leader) Prof. Sumit Chandak (Team Member 1) Dr. Rakesh Kumar Malviya (Team Member 2)

ENGINEERING CURVES Conic Sections Ellipse Parabola Hyperbola

β α β α β< α β> α α β β= α CONIC SECTIONS ELLIPSE, PARABOLA AND HYPERBOLA ARE CALLED CONIC SECTIONS BECAUSE THESE CURVES APPEAR ON THE SURFACE OF A CONE WHEN IT IS CUT BY SOME TYPICAL CUTTING PLANES. OBSERVE ILLUSTRATIONS GIVEN BELOW.. Ellipse e<1 β α α β β< α β> α Section Plane Through all the Generators Section Plane Inclined at an angle Greater than that of end generator. Hyperbola e>1 α β β= α Parabola Section Plane Parallel to end generator. e=1

Terminology

What is eccentricity ? Conic section Directrix A P N Axis C D V F Focus Vertex B Distance from focus PF VF eccentricity = = = Distance from directrix PN VC

SECOND DEFINATION OF AN ELLIPSE:- These are the loci of points moving in a plane such that the ratio of it’s distances from a fixed point And a fixed line always remains constant. The Ratio is called ECCENTRICITY. (E) For Ellipse E<1 For Parabola E=1 For Hyperbola E>1 SECOND DEFINATION OF AN ELLIPSE:- It is a locus of a point moving in a plane such that the SUM of it’s distances from TWO fixed points always remains constant. {And this sum equals to the length of major axis.} These TWO fixed points are FOCUS 1 & FOCUS 2 COMMON DEFINATION OF ELLIPSE, PARABOLA & HYPERBOLA:

SECOND DEFINATION OF AN ELLIPSE:- B F1 F2 AB: Major Axis D CD: Minor Axis PF1+PF2=Constant=AB= Major Axis SECOND DEFINATION OF AN ELLIPSE:- It is a locus of a point moving in a plane such that the SUM of it’s distances from TWO fixed points always remains constant. {And this sum equals to the length of major axis.} These TWO fixed points are FOCUS 1 & FOCUS 2

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