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GrimesA

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< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >

So the problem that I have been assigned has formulas of

**rotational energy, momentum, trajectories, inertia,**and

**inclined planes.**A solid sphere is rolling down an inclined plane (that is placed on a table) and then off of the table (losing 4% of energy before it leaves the table). I must predict where the final distance on the ground the ball will land and show algebraic solutions.

I broke the part into two separate problems. One of

**inclined plane**/

**rotational energy**which leads me to the

**trajectory**problem.

To set up the

**inclined plane**to solve for the velocity that it leaves the table at I found that PE=KE. Therefore

*mgh=½mv^2 + ½((2/5)MR^2)(v/R)^2*which I then simplified to

*2g*h=v^2(1+(2/5))*and finally to solve for Vf I said √

*2g*h (minus the 4%)/(1+(2/5)) = Vf*

Now it is time for the part I was confused on. I originally started the

**trajectory**problem solving in the Y to find the time it'll hit the ground in. I found that

*Yf= Yi+Vit+½at^2*and so

*t=√2*Yi/gravity*which I then used to find Xf by saying

*Xf=Vi*t.*

However, upon inspection I realized that I hadn't accounted for the angle of the inclined plane nor the fact that when I went from

*Yf= Yi+Vit+½at^2*to being

*t=√2*Yi/gravity*I had made Vi of Y to be zero which I know applies to situation that the object is DROPPED where this was is already moving in both X and Y as the problem started. I am cloudy-minded on how to rectify my incorrections.

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