Answer:
The number of vacancies per cubic meter is 1.18 X 10²⁴ m⁻³
Explanation:
![N_v = N*e[^{-\frac{Q_v}{KT}}] = \frac{N_A*\rho _F_e}{A_F_e}e[^-\frac{Q_v}{KT}}]](https://tex.z-dn.net/?f=N_v%20%3D%20N%2Ae%5B%5E%7B-%5Cfrac%7BQ_v%7D%7BKT%7D%7D%5D%20%3D%20%5Cfrac%7BN_A%2A%5Crho%20_F_e%7D%7BA_F_e%7De%5B%5E-%5Cfrac%7BQ_v%7D%7BKT%7D%7D%5D)
where;
N
is the number of atoms in iron = 6.022 X 10²³ atoms/mol
ρFe is the density of iron = 7.65 g/cm3
AFe is the atomic weight of iron = 55.85 g/mol
Qv is the energy vacancy formation = 1.08 eV/atom
K is Boltzmann constant = 8.62 X 10⁻⁶ k⁻¹
T is the temperature = 850 °C = 1123 k
Substituting these values in the above equation, gives
![N_v = \frac{6.022 X 10^{23}*7.65}{55.85}e[^-\frac{1.08}{8.62 X10^{-5}*1123}}]\\\\N_v = 8.2486X10^{22}*e^{(-11.1567)}\\\\N_v = 8.2486X10^{22}*1.4279 X 10^{-5}\\\\N_v = 1.18 X 10^{18}cm^{-3} = 1.18 X 10^{24}m^{-3}](https://tex.z-dn.net/?f=N_v%20%3D%20%5Cfrac%7B6.022%20X%2010%5E%7B23%7D%2A7.65%7D%7B55.85%7De%5B%5E-%5Cfrac%7B1.08%7D%7B8.62%20X10%5E%7B-5%7D%2A1123%7D%7D%5D%5C%5C%5C%5CN_v%20%3D%208.2486X10%5E%7B22%7D%2Ae%5E%7B%28-11.1567%29%7D%5C%5C%5C%5CN_v%20%3D%208.2486X10%5E%7B22%7D%2A1.4279%20X%2010%5E%7B-5%7D%5C%5C%5C%5CN_v%20%3D%201.18%20X%2010%5E%7B18%7Dcm%5E%7B-3%7D%20%3D%201.18%20X%2010%5E%7B24%7Dm%5E%7B-3%7D)
Therefore, the number of vacancies per cubic meter is 1.18 X 10²⁴ m⁻³
W = mg, Assuming g ≈ 9.8 m/s² on the earth surface.
735 N = m* 9.8
735/9.8 = m
75 = m
Mass , m = 75 kg. B.
If Earth's mass was increased, its gravity would also increase. Things on Earth would weigh more.
The work done to pull the sled up to the hill is given by
where
F is the intensity of the force
d is the distance where the force is applied.
In our problem, the work done is
and the distance through which the force is applied is
, so we can calculate the average force by re-arranging the previous equation and by using these data:
