User's Manual

012–07192A Discover Density Set
11
The straight-line graph (Figure 5) is confirmation that y = c x
k
was indeed the
form of the equation. The slope of this graph is 3, showing that the exponent
k is 3.
The constant c may be evaluated by various methods. Perhaps the best is by
solving the equation for c, and substituting data from the original table.
Given that y = c x
3
,
c = y / x
3
, and substituting
x = 2.7 cm, y = 29.5 g (from the next-to-last data pair; any data pair
could have been used)
c = (29.5 g) / (2.7 cm)
3
,
c = 1.50 g/cm
3
Substituting this value, and the symbols e and
m (for edge and mass), the final equation is
m = (1.50 g/cm
3
) e
3
.
Figure 5
Graph of the log
transformation of the
experimental data