Conservation of Energy/Angular Momentum

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SUMMARY

The discussion focuses on the application of the conservation of energy principle to determine the maximum height a wooden block of mass m reaches on a rough incline with a coefficient of kinetic friction, uk. The key equation derived is h = [mvi^2 - ukmgcos(theta)d]/mg, where d represents the distance traveled up the ramp. Participants clarify that d must be expressed as a function of h and theta, and emphasize the importance of distinguishing between different heights (H) in the problem statement. The discussion also touches on the conservation of mechanical energy for a hoop with radius R, incorporating both linear and angular velocities.

PREREQUISITES
  • Understanding of conservation of energy principles
  • Knowledge of kinetic and potential energy equations
  • Familiarity with the concepts of friction and incline angles
  • Basic understanding of rotational motion and angular velocity
NEXT STEPS
  • Explore the derivation of energy equations in inclined planes
  • Study the effects of friction on motion in physics
  • Learn about rotational kinetic energy and its applications
  • Investigate the relationship between linear distance and angle in inclined motion
USEFUL FOR

Students studying physics, particularly those focusing on mechanics, energy conservation, and motion on inclined planes. This discussion is beneficial for anyone tackling problems involving kinetic friction and energy transformations.

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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
 

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