Question

5. a) Define viscosity. 

b) A matter has a body-centered cubic unit cell with a length of 330 𝑝𝑚 along an edge

and a density of 8.57 𝑔 𝑐𝑚−3

. Calculate the atomic mass of the matter.

c) Find the total energy of a moving object of mass 6.3 𝑘𝑔 and momentum

11.5 × 106 𝑘𝑔𝑚𝑠

−1

.

Answer 1

a) Viscosity is a property of fluid to resist the changes in its density.

b) The atomic mass:

$$M=\frac{\rho N_aa^3}{2}=0.093\text{ kg/mol}.$$

c) The energy is

$$E=\frac{p^2}{2m}=1.2·10^{20}\text{ J}.$$