If ABCD is a parallelogram, vector AB = 2i + 4j - 5k and vector AD = i + 2j + 3k, then the unit vector in the direction of BD is
\(\frac{1}{√69}(\hat{i}+2\hat{j}-8\hat{k})\)
\(\frac{1}{69}(\hat{i}+2\hat{j}-8\hat{k})\)
\(\frac{1}{√69}(\hat{-i}-2\hat{j}+8\hat{k})\)
\(\frac{1}{69}(\hat{-i}-2\hat{j}+8\hat{k})\)
The correct answer is option C) \(\frac{1}{√69}(\hat{-i}-2\hat{j}+8\hat{k})\)

Which one of the following graphs accurately represents the plot of partial pressure of CS₂ vs its mole fraction in a mixture of acetone and CS₂ at constant temperature?

In the given figure, the blocks $A$, $B$ and $C$ weigh $4\,\text{kg}$, $6\,\text{kg}$ and $8\,\text{kg}$ respectively. The coefficient of sliding friction between any two surfaces is $0.5$. The force $\vec{F}$ required to slide the block $C$ with constant speed is ___ N.
(Given: $g = 10\,\text{m s}^{-2}$) 