contestada

A water hose is used to fill a large cylindrical storage tank of



distance diameter D and height 2D. The hose shoots the water at 45°



above the horizontal from the same level as the base of the tank and is a



distance 6D away. For what range of launch speeds will the water enter



the tank? Ignore air resistance, and express your answer in terms of D



and g.

Respuesta :

Answer:

maximum possible speed by solving above equation for 7D is

[tex]v_{max} = \sqrt{\frac{49}{5}gD}[/tex]

minimum possible value of speed for solving x = 6D is given as

[tex]v_{min} = \sqrt{9gD}[/tex]

Explanation:

Let the nozzle of the hose be at the origin. Then the nearest part of the rim of the tank is at (, ) =  (6, 2) and the furthest part of the rim is at (, ) = (7, 2).

The trajectory of the water can be found as follows:

[tex]x = (v_o cos45) t[/tex]

[tex]y =  (v_o sin45) t - \frac{1}{2}gt^2[/tex]

Now from above two equations we have

[tex]y = x - \frac{gx^2}{v_o^2}[/tex]

now we know that height of the cylinder is 2D so we have

[tex]x - \frac{gx^2}{v_o^2} = 2D[/tex]

by solving above equation we have

[tex]x = \frac{v_o^2 \pm v_o^2\sqrt{1 - \frac{8gD}{v_o^2}}}{2g}[/tex]

now we know that maximum value of x is 7D

so the maximum possible speed by solving above equation for 7D is

[tex]v_{max} = \sqrt{\frac{49}{5}gD}[/tex]

minimum possible value of speed for solving x = 6D is given as

[tex]v_{min} = \sqrt{9gD}[/tex]