Anand Jangid, Tutor at Private classes, Numerade Educator

Physics 101 Mechanics

Worksheet for Exploration 14.1:
Floating and Density
How can a boat made out of a material
more dense than water float? The block has a mass of 0.185 kg
(position is given in centimeters). If this block
is a cube, what is the density of the block? Note that
since it is greater than water (1000 kg/m^3) the block
sinks as shown in the animation. Restart.
Block Density=

We reshape the block so that it has
the same depth into the screen, but is wider and taller with walls
that are 0.21 cm thick.
When the animation runs, what is the volume of water displaced
(the dimension of the water container into the screen that you
cannot see is 10 cm)?
First sketch a free
body force diagram for forces acting on the reshaped box. (One of
these is the buoyant force). You can use "Insert" , and
"Shapes"
Displaced water: Length=
Width=

Depth=

Volume displaced=

Using the density of water (1000 kg/m^3), find the
mass of the water displaced. Show that it is equal to the mass of
the reshaped block. Thus, the block floats.
Think about how mass, density and
volume all relate.
mass of water=
Another way to think about this is that in its new shape the
block has an effective density (total mass/total volume) less than
that of the water. Divide the mass (0.185 kg) by the new volume to
find the new effective density of the block.
Effective Block Density=
How does the effective density compare to the density of
water?
The weight (mass*9.8
m/s^2) of the water displaced (even if the displaced
water leaves the container) is equal to the buoyant force on the
block. In the case of a floating object, the buoyant force is equal
to the weight of the floating object.