M.1.A

Video

It’s about the angular position. Consider the position of the second arm on a clock face. Proceed as follows.

Steps

1. Angular Position

../../../_images/M.1.A.png

Angle describes angular position

Conventions for angle \(\varphi\):

  • Domain: \(0^\circ \le \varphi < 360^\circ\)

  • Origin: \(\varphi=0^\circ\) at 3 o’clock position

  • Counting direction: Counter clockwise

Fill in the table below:

Ang. Position

\(0^\circ \le \varphi < 360^\circ\)

2 o’clock

\(30^\circ\)

12 o’clock

\(90^\circ\)

6 o’clock

\(\ldots\)

11 o’clock

\(\ldots\)

4 o’clock

\(\ldots\)

5 o’clock

\(\ldots\)

Solution

Ang. Position

\(0^\circ \le \varphi < 360^\circ\)

2 o’clock

\(30^\circ\)

12 o’clock

\(90^\circ\)

6 o’clock

\(270^\circ\)

11 o’clock

\(120^\circ\)

4 o’clock

\(330^\circ\)

5 o’clock

\(300^\circ\)

2. Periodicity

../../../_images/M.1.A_2.png

360 Degrees Periodicity

One arm position can be described with multiple angles. All angles below describe the “2 o’clock” arm position:

\[\begin{split}\varphi &= 30^\circ \\ \varphi &= 390^\circ \\ \varphi &= 750^\circ\end{split}\]

Fill in the table below.

Ang. Position

\(0^\circ \le \varphi < 360^\circ\)

\(360^\circ \le \varphi < 720^\circ\)

2 o’clock

\(30^\circ\)

\(390^\circ\)

12 o’clock

\(90^\circ\)

\(450^\circ\)

6 o’clock

\(\ldots\)

\(\ldots\)

11 o’clock

\(\ldots\)

\(\ldots\)

4 o’clock

\(\ldots\)

\(\ldots\)

5 o’clock

\(\ldots\)

\(\ldots\)

Solution

Ang. Position

\(0^\circ \le \varphi < 360^\circ\)

\(360^\circ \le \varphi < 720^\circ\)

2 o’clock

\(30^\circ\)

\(390^\circ\)

12 o’clock

\(90^\circ\)

\(450^\circ\)

6 o’clock

\(270^\circ\)

\(630^\circ\)

11 o’clock

\(120^\circ\)

\(480^\circ\)

4 o’clock

\(330^\circ\)

\(690^\circ\)

5 o’clock

\(300^\circ\)

\(660^\circ\)

3. Counting Direction

../../../_images/M.1.A_3.png

Negative Angles

One arm position can be described with multiple angles. All angles below describe the “2 o’clock” arm position:

\[\begin{split}\varphi &= -330^\circ \\ \varphi &= -690 ^\circ \\ \varphi &= \ldots\end{split}\]
  • The green arrow indicates the direction, in which \(\varphi\) grows.

  • The red arrow indicates the direction, in which \(-\varphi\) grows.

Fill in the table below.

Ang. Position

\(0^\circ \le \varphi < 360^\circ\)

\(0^\circ \le - \varphi < 360^\circ\)

\(-360^\circ < \varphi \le 0^\circ\)

2 o’clock

\(30^\circ\)

\(330^\circ\)

\(-330^\circ\)

12 o’clock

\(90^\circ\)

\(270^\circ\)

\(-270^\circ\)

6 o’clock

\(\ldots\)

\(\ldots\)

\(\ldots\)

11 o’clock

\(\ldots\)

\(\ldots\)

\(\ldots\)

4 o’clock

\(\ldots\)

\(\ldots\)

\(\ldots\)

5 o’clock

\(\ldots\)

\(\ldots\)

\(\ldots\)

Solution

Ang. Position

\(0^\circ \le \varphi < 360^\circ\)

\(0^\circ \le - \varphi < 360^\circ\)

\(-360^\circ < \varphi \le 0^\circ\)

2 o’clock

\(30^\circ\)

\(330^\circ\)

\(-330^\circ\)

12 o’clock

\(90^\circ\)

\(270^\circ\)

\(-270^\circ\)

6 o’clock

\(270^\circ\)

\(90^\circ\)

\(-90^\circ\)

11 o’clock

\(120^\circ\)

\(240^\circ\)

\(-240^\circ\)

4 o’clock

\(330^\circ\)

\(30^\circ\)

\(-30^\circ\)

5 o’clock

\(300^\circ\)

\(60^\circ\)

\(-60^\circ\)

4. Degrees and Radians

../../../_images/M.1.A_4.png

Fill in the table below.

Ang. Position

\(0^\circ \le \varphi < 360^\circ\)

\(0 \le \varphi < 2 \pi\)

\(- 2 \pi < \varphi \le 0\)

2 o’clock

\(30 ^\circ\)

\(\tfrac{1}{12} \cdot 2\pi\)

\(-\tfrac{11}{12} \cdot 2\pi\)

12 o’clock

\(90 ^\circ\)

\(\tfrac{3}{12} \cdot 2\pi\)

\(-\tfrac{9}{12} \cdot 2\pi\)

6 o’clock

\(\ldots\)

\(\ldots\)

\(\ldots\)

11 o’clock

\(\ldots\)

\(\ldots\)

\(\ldots\)

4 o’clock

\(\ldots\)

\(\ldots\)

\(\ldots\)

5 o’clock

\(\ldots\)

\(\ldots\)

\(\ldots\)

Solution

Ang. Position

\(0^\circ \le \varphi < 360^\circ\)

\(0 \le \varphi < 2 \pi\)

\(- 2 \pi < \varphi \le 0\)

2 o’clock

\(30 ^\circ\)

\(\tfrac{1}{12} \cdot 2\pi\)

\(-\tfrac{11}{12} \cdot 2\pi\)

12 o’clock

\(90 ^\circ\)

\(\tfrac{3}{12} \cdot 2\pi\)

\(-\tfrac{9}{12} \cdot 2\pi\)

6 o’clock

\(270^\circ\)

\(\tfrac{9}{12} \cdot 2\pi\)

\(-\tfrac{3}{12} \cdot 2\pi\)

11 o’clock

\(120^\circ\)

\(\tfrac{4}{12} \cdot 2\pi\)

\(-\tfrac{8}{12} \cdot 2\pi\)

4 o’clock

\(330^\circ\)

\(\tfrac{11}{12}\cdot 2\pi\)

\(-\tfrac{1}{12} \cdot 2\pi\)

5 o’clock

\(300^\circ\)

\(\tfrac{10}{12}\cdot 2\pi\)

\(-\tfrac{2}{12} \cdot 2\pi\)

5. Choices

../../../_images/M.1.A_5.png

Choose symbol, origin and counting direction

Winkel werden zur Beschreibung der Winkelposition des Zeigers verwendet. Hierbei wählt man die Bezeichnung des Winkels, den Nullpunkt und die Zählrichtung:

Fill in the table below.

Ang. Position

\(0^\circ \le \psi < 360^\circ\)

\(0 \le \psi < 2 \pi\)

7 o’clock

\(30 ^\circ\)

\(\tfrac{1}{12} \cdot 2\pi\)

9 o’clock

\(90 ^\circ\)

\(\tfrac{3}{12} \cdot 2\pi\)

6 o’clock

\(\ldots\)

\(\ldots\)

11 o’clock

\(\ldots\)

\(\ldots\)

4 o’clock

\(\ldots\)

\(\ldots\)

5 o’clock

\(\ldots\)

\(\ldots\)

Solution

Ang. Position

\(0^\circ \le \psi < 360^\circ\)

\(0 \le \psi < 2 \pi\)

7 o’clock

\(30 ^\circ\)

\(\tfrac{1}{12} \cdot 2\pi\)

9 o’clock

\(90 ^\circ\)

\(\tfrac{3}{12} \cdot 2\pi\)

6 o’clock

\(0^\circ\)

\(\tfrac{0}{12} \cdot 2\pi\)

11 o’clock

\(150^\circ\)

\(\tfrac{5}{12} \cdot 2\pi\)

4 o’clock

\(300^\circ\)

\(\tfrac{10}{12}\cdot 2\pi\)

5 o’clock

\(330^\circ\)

\(\tfrac{11}{12}\cdot 2\pi\)

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Angles