Conservation of Energy/Angular Momentum

AI Thread Summary
The discussion revolves around solving a physics problem involving the conservation of energy for a wooden block sliding up an incline with friction. The key equation derived is mgh + Fd = 1/2mv^2, where the challenge lies in determining the distance d traveled up the ramp. Participants suggest expressing d as a function of height h and angle theta to simplify the calculations. Additionally, there is confusion regarding the notation of height H from part (a) and how it relates to the current problem. Ultimately, the focus is on correctly applying conservation principles to find the maximum height the block reaches.
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Homework Statement


Hi.
The problem is "A wooden block of mass m slides with an initial speed of vi up a straight incline that makes an angle of theta with the horizontal. If the incline is rough with a coefficient of kinetic friction uk, determine the maximum height it rises in terms of h found in part a (which was H = vi^2/2g)"


Homework Equations


conservation of energy
You can only use m (mass of block), vi (initial velocity), theta, and g (gravity)


The Attempt at a Solution


KE at the bottom = PE at the top + Work.
mgh + Fd = 1/2mv^2
h = [mvi^2 - ukmgcos(theta)d]/mg
Problem is, I don't know what d is and it can't be part of my final answer. I know it's the distance that the block travels up the ramp, but how do I figure that out?
Also, since it says in terms of h found in part a, does that mean I set everything equal to vi^2/2g?

How would I do this with a hoop with radius R?
 
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So, you correctly applied the conservation of mechanical energy. :smile:
Could you right d as a function of h and \theta? :rolleyes:

The hoop will have in the end not only linear velocity but also angular velocity. Apply again conservation of mechanical energy, but this time consider also the kinetic rotational energy. :-p
 
Okay this is going to sound really confusing but am I on the right path for the block one?

I got to the point where gh = 1/2(vi)^2 - ukg(cot(theta))h
At this point, do I plug in what I got for H in part (a) since it wants it says "in terms of h found in part a"? What exactly are they asking me to do?
 
Nevermind. I was being stupid and forgot they are two different H's
 
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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