Page 101 - Making things move_ DIY mechanisms for inventors, hobbyists, and artists
P. 101
82 Making Things Move
Recipe:
1. Position your protractor at the pivot point of the scrap wood board, as shown
in Figure 4-9.
2. Place the first object (the clay block) on the board.
3. Increase the angle until the block just starts to slide.
4. Read the angle.
5. Repeat steps 2 and 3 three times, and take the average measurement. In this
test, I found the clay slipping at 45°.
6. Repeat steps 2 though 5 with the second object (the iPhone). I found the
iPhone slipping at just 12°.
FIGURE 4-9 Friction testing
