Second Year Homework 08/Sept/17

Technical Graphic is one of two Technology subjects offered to students in CBS Wexford. In Technical Graphics students learn to represent real life 3 dimensional objects in 2D on paper or the computer.

**THIRD YEAR NOTES:**

**Section A: Short Questions**

**PERSPECTIVE**

All parallel line vanish to the same vanishing point.

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The diagrams below are a breakdown of the solution to the perspective short question in 2016. It was Question 2 in Section A.

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The diagrams below are a breakdown of the solution to the perspective short question in 2015. It was Question 2 in Section A.

Perspevtive Storyboards:

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**FREEHAND SKETCHING**

This style of question appears as two in Section A every year. One of these questions will provide a grid. Both must be completed freehand and shaded to pick up all the marks available.

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**AREA CONVERSIONS**

**TANGENTS TO A POINT ON A CIRCLE**

**To draw a tangent to a circle at a given point on the circumference of a circle.**

First draw a line from the centre of the circle through the point of contact. This line is the called the normal. It is at 90° to the tangent.

Now to draw a line through the point of contact that is at 90° to the normal. This is the tangent to the circle at point P.

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**To draw a tangent to a circle from a given point outside the circumference of a circle.**

The construction of a tangent to a circle from a point outside the circumference of the circle is based on the angle in a semicircle theorem. To draw the tangent first draw a line from the point Q to the centre of the circle.

Now bisect the distance between the centre and Q.

This finds the centre of a semicircle that passes through C and Q. Draw a semicircle passing through these points.

This semicircle cuts the circle at the point of contact between the tangent and the circle. Label the point of contact P.

Once P, the point of contact, has been found then draw the tangent through the points Q and P.

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The diagrams below are a breakdown of the solution to the Tangent short question in 2016. It was Question 14 in Section A.

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Tangents to Circle Storyboards:

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**CIRCLES IN CONTACT/ DIVISION OF LINES**

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**CONIC SECTIONS**

The diagram below shows the solution to the Conic Sections short question in 2016. It was Question 1o in Section A.

Conic Sections Storyboards

TG Conic Sections Storyboard 1

TG Conic Sections Storyboard 2

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**CAD COMMANDS**

This CAD commands question is generally in Section A every year. The diagrams below are the solutions to the CAD short question in 2015, 2016. It was Question 9 in Section A.

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**ORTHOGRAPHIC PROJECTION AND AUXILIARY VIEWS**

This topic is generally in Section A every year. The diagrams below are the solutions to the question in 2016. It was Question 9 in Section A.

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** SOLIDS IN CONTACT**

This question is generally in Section A every year. The diagrams below are the solutions to the short question in 2016. It was Question 11 in Section A.

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**REDUCING AND ENLARGING**

Reducing and Enlarging Storyboards

TG Reducing By Polar Projection

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**Section B: Long Questions**

This topic appears in Section B of the Technical Graphics higher level paper. It is generally Question 1. This question will include the construction of a plan, elevation and end-view of a given object. These object will usually contain a cut cylinder. Also a true shape of on of the surfaces is generally required.

Click the title to move to the Orthographic Projection Page.

This topic appears in Section B of the Technical Graphics higher level paper. It is generally Question 2. This question will include the construction of a plan, elevation and end-view of a given object. These object will contain a surface that is rotated around a hinge. Drawing this surfaces in its rotated position is generally required.

Click the title to move to the Orthographic Projection Page.

This topic appears in Section B of the Technical Graphics higher level paper. It is generally Question 5. This question will include the construction of a logo or image and four transformations of this image. These transformations will be a translation, axial symmetry, central symmetry and a rotation.

Click the title to move to the Transformation Geometry Page.

Click the title to move to the Transformation Geometry Page.