Initial Velocity of a Projectile

AI Thread Summary
To determine the initial velocity of a projectile launched from a slingshot that clears a 10-meter fence and lands 10 meters behind it, the problem can be divided into two segments: the trajectory up to the fence and the trajectory after. The horizontal distance to the fence is 130 meters, while the total distance traveled is 140 meters. The vertical motion can be analyzed using the equations of motion, with the vertical displacement being zero upon landing. It is crucial to note that the initial velocity for the second segment must equal the final velocity from the first segment, rather than assuming it is zero. Understanding these principles is essential for accurately solving the problem.
AngeliaGW
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Homework Statement



A ball is shot from a slingshot and clears a 10 meter fence 130 meters from the point of being flung and lands 10 meters behind the fence. What is the initial velocity of the ball? Assume the ball was caught at the same level it was kicked (delta Y=0).


Homework Equations



Delta Y=Voyt+1/2at^2
Delta Y=Vfy^2-Voy^2/at
Delta X=Voxt

The Attempt at a Solution



I'm unsure how to solve this problem as it involves multiple unknown variables. I think it involves 2 separate problems, one that is up to the fence and one that is after the fence. So 130=Voxt and 140=Voxt. For Delta Y, it would be Voy=4.9t. Please help :(
 
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Is it possible to assume that right when the ball passes the fence, that the initial velocity is 0 if I divide the problem into two? (One up to the fence, and one after the fence)
 
AngeliaGW said:
Is it possible to assume that right when the ball passes the fence, that the initial velocity is 0 if I divide the problem into two? (One up to the fence, and one after the fence)
No.

You can divide it in two, but the initial velocity for the second part should be the same as the final velocity from the first part.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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