Which has a greater buoyant force on it, a 27.0-cm3 piece of wood floating with part of its volume above water or a 27.0-cm3 piece of submerged iron?

a. the floating wood the submerged iron
b. they have the same buoyant force on them.
c. it is impossible to tell without knowing their weights.

The submerged iron.

Explanation:

Any body submerged in a liquid (it doesn't matter if it is partially or fully submerged) is acted on by an upward force, which is equal to the weight of the volume of liquid removed by the body.

If the wood and the iron have the same volume, but the wood is only in part submerged, the volume of water displaced by the body, will be only equal to the fraction of the total volume submerged.

In the case of the iron, the buoyant force can be expressed as follows:

Fbi  = ρ(H2O) * Viron * g

Now, the volume  actually submerged of the piece of wood, is just a fraction of the total volume (which is equal to the iron volume), so we can write the following equation:

Vw = k* Viron (where k < 1)

If we replace in (1), we have:

Fbw = ρ(H2O) * k*Viron * g

As k < 1, it is clear that Fbi > Fbw.

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.