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" A 4 kg ball is thrown at an angle of 40 degrees above the horizon from the top of a 150 m cliff. How far from the base of the cliff does it land of the initial velocity is 30 m/s

Respuesta :

Answer: 180.102m

Explanation:

This situation is a good example of the projectile motion or parabolic motion, in which the travel of the ball after it is thrown from the top of the cliff has two components: x-component and y-component. Being their main equations as follows:

x-component:

[tex]x=V_{o}cos\theta t[/tex]   (1)

Where:

[tex]V_{o}=30m/s[/tex] is the ball's initial speed

[tex]\theta=40\°[/tex] is the angle above the horizon

[tex]t[/tex] is the time since the ball is thrown until it hits the ground

y-component:

[tex]y=y_{o}+V_{o}sin\theta t-\frac{gt^{2}}{2}[/tex]   (2)

Where:

[tex]y_{o}=150m[/tex]  is the initial height of the ball

[tex]y=0[/tex]  is the final height of the ball (when it finally hits the ground)

[tex]g=9.8m/s^{2}[/tex]  is the acceleration due gravity

Knowing this, let's begin with the calculations:

Firstly, we have to find the time the ball elapsed traveling. So, we will use equation (2) with the conditions given above:

[tex]0=y_{o}+V_{o}sin\theta t-\frac{gt^{2}}{2}[/tex] (3)  

Isolating [tex]t[/tex] from (3):  

[tex]t=\frac{V_{o}}{g}(sin\theta+\sqrt{{sin\theta}^{2}+2\frac{g.y_{o}}{V_{o}^{2}}})[/tex] (4)  

[tex]t=7.83s[/tex] (5)  

Substituting (5) in (1):  

[tex]x_{max}=30m/s.cos(40\°) (7.83)[/tex]   (6)  

Finally:

[tex]x_{max}=180.102m[/tex]   (7)  

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