The triangulation board has a tiltable arm with a laser pointer on it.
We use the following procedure to measure the distance across the lecture hall.
- A distant point on the wall is sighted by aiming the laser pointer horizontally
along the top horizontal black line on the board.
- The arm is then moved to the bottom horizontal black line and tilted upward
until the laser pointer aims at the same point as in step 1.
|
- The deviation of the tip of the arm above the lower horizontal line
can be measured on the scale. In this case the value is 4.5 cm or 0.045 m.
- Other data needed to determine the distance are
- the distance between horizontal black lines, 0.7 m and
- the distance from the arm's pivot point to the scale at its tip, 0.8 m.
|