A firefighting crew uses a water cannon that shoots water at 30.0 m/s at a fixed angle of 45.0 ∘ above the horizontal. The firefighters want to direct the water at a blaze that is 10.0 m above ground level. How far from the building should they position their cannon? There are two possibilities (d1

Respuesta :

Answer:

The distance from the building is 11.41 m.

Explanation:

Given that,

Speed = 30.0 m/s

Angle = 45.0°

Distance = 10.0 m

We need to calculate the vertical component

Using formula of vertical component

[tex]u_{y}=u\sin\theta[/tex]

[tex]u_{y}=30.0\times\sin45[/tex]

[tex]u_{y}=21.21\ m/s[/tex]

We need to calculate the time

Using equation of motion

[tex]s=ut-\dfrac{1}{2}gt^2[/tex]

Put the value into the formula

[tex]10=21.21t-\dfrac{1}{2}\times9.8\times t^2[/tex]

[tex]21.21t-\dfrac{1}{2}\times9.8\times t^2-10=0[/tex]

[tex]-4.9t^2+21.21t-10=0[/tex]

[tex]t=0.538\ sec[/tex]

On neglecting of higher value of t

Then use the horizontal component

[tex]u_{y}=u\cos\theta[/tex]

[tex]u_{x}=30.0\times\cos45[/tex]

[tex]u_{x}=21.21\ m/s[/tex]

We need to calculate the distance

[tex]d=v\times t[/tex]

Put the value into the formula

[tex]d=21.21\times0.538[/tex]

[tex]d=11.41\ m[/tex]

Hence, The distance from the building is 11.41 m.