One method used to determine the volume of solids and liquids is displacement true or faluse

In ancient times, the use of water displacement method has proved useful to find the densities of specific substances even without the right scaling. The displacement method is used to measure the volume of a solid object no matter what form it may be. When the solid object is immersed in the water, the rise or increase of water level from its initial level is said to be the density of that solid. The displaced water is the density of the solid. 

c) particle with sharp ends

Explanation:

Rate of deposition of a particle determines how fast a particle of given characteristics (size, shape etc) will settle onto a surface. This is explained in terms of the Stokes law, according to which the frictional force (F) or the Stokes drag acting between the particle and the medium is proportional to the particle radius (R), flow velocity (v) and viscosity (μ)

F =  6πμRv

The frictional force which is essentially offers resistance to the flow will be the highest for irregularly shaped particles particles in this case those with sharp ends. As a result, these particles would have the slowest rate of deposition.