Answer to Question #136584 in Physics for Roxie

Question

The length of a pencil was measured using a ruler. Find (a) best estimate of the lenght of the pencil, (b) the least count of the ruler, (c) the length of the pencil when pressed in terms of absolute uncertainty, and (d) length of the pencil when pressed in terms of relative uncertainty.
Convert 15cm to mm.

Answer 1

(a) Best estimate of the length of the pencil is 14.3 cm

(b) The least count of my ruler is 1 mm

(c) The length of the pencil when pressed in terms of absolute uncertainty is

$$L=(14.3\pm0.01)\text{ cm}.$$

(d) The length of the pencil when pressed in terms of relative uncertainty:

$$L=14.3\text{ cm}, \space\\\epsilon=\frac{0.01}{14.3}\cdot100\%=0.07\%.$$

15 cm is 150 mm.