Question

Determine the height above the dashed line XX' attained by the water stream coming out through the hole is situtated at point B in the diagram given below. Given that $h=10\text{m},L=2\text{m}\text{and}d={30}^{\circ }$.

• A. $10\text{m}$
• B. $7.1\text{m}$
• C. $5\text{m}$
• D. $3.25\text{m}$

Answer 1

The correct option is D $3.25\text{m}$

Let the velocity at point B is $v_B,$
From conservation total mechanical energy,
$mg[h-Lsin\alpha ]=\frac{1}{2}m{v}_B^2$
$\Rightarrow v_B^2=2g(h-Lsin\alpha )=2g(10-2\times \frac{1}{2})$
$\Rightarrow v_B^2=18g$
Now, let maximum height attained by water stream, be (H)
$H=L\sin \alpha +\frac{v_B^2{\sin }^2\alpha }{2g}$
$\Rightarrow H=2\times \frac{1}{2}+\frac{18g{\left(\frac{1}{2}\right)}^2}{2g}=1+\frac{18}{8}=3.25\text{m}$
Here, the correct answer is option (d).