g A 4 cm diameter "bobber" with a mass of 3 grams floats on a pond. A thin, light fishing line is tied to the bottom of the bobber, and from the bottom hangs a 10 gram lead weight. The density of lead is 11.3 g/cm3. What fraction of the bobber's volume is submerged, as a percent of the total volume

total weight acting downwards

= 3g + 10g

13 g

volume of lead = 10 / 11.3 =.885 cm³

Let the volume of bobber submerged in water be v in floating position. buoyant force on bobber = v x 1 x g

Buoyant force on lead =.885 x 1 x g

total buoyant force = vg +.885 g

For floating

vg +.885 g = 13 g

v = 12.115 cm³

total volume of bobber

= 4/3 x 3.14 x 2³

= 33.5 cm³

fraction of volume submerged

= 12.115 / 33.5

=.36

= 36 %