Trebuchet Help: Calculating Final Velocity & Acceleration

AI Thread Summary
The discussion revolves around calculating the final velocity and acceleration of a tennis ball launched from a trebuchet. A user seeks help with the correct equations, initially confused by their teacher's guidance on using F=m(v^2/r) for initial velocity. Another participant clarifies that the initial and final velocities are the same if air resistance is ignored and the launch and target heights are equal. They also suggest using the conservation of energy principle if the heights differ. The user expresses gratitude after understanding the concepts, despite having already submitted their report.
elvalil
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Trebuchet help!

1. Hi, I am writing a report for a trebuchet project, and trying to find the final velocity of the tennis ball, my teacher told us to just use this :F=m(v^2/r) for initial velocity. so I am really confused right now. I don't know how to find final velocity. Also, which equation do I use for acceleration? A=change in v/ total time; or v^2/t ? /I will just post one set of data.: Range: 7.3m; time :.98s; initial velocity: 5.981m/s.

Please Help..Its Due Tomorrow..AND I am STUCK on this..=[...
THANK U !
 
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Welcome to PF!

elvalil said:
Hi, I am … trying to find the final velocity of the tennis ball, my teacher told us to just use this :F=m(v^2/r) for initial velocity …

Hi elvalil! Welcome to PF! :wink:

Yes, your teacher is right, because the initial and final velocities will be the same (if we ignore air resistance), provided the trebuchet is at the same height as the target. :smile:

(and if it isn't, just use KE + PE = constant :wink:)
 


Thank you!
haha ..it was due today..
so I got my grade already...

but oh well..
thanks anyways...
now that I understand it completely.
thxx=]
 
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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