Solving for Kinetic Energy with Circular Wheel and Weight: Equation Included

  • Thread starter Thread starter Momentum09
  • Start date Start date
  • Tags Tags
    Torque
Click For Summary

Homework Help Overview

The discussion revolves around calculating the total kinetic energy of a system involving a circular wheel and a falling weight. The wheel has a defined moment of inertia, and the participants are exploring how to incorporate both translational and rotational kinetic energy into the equation.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the need to account for both the rotational kinetic energy of the wheel and the translational kinetic energy of the falling weight. There is an inquiry about the appropriate equations to use and how to combine these energy terms.

Discussion Status

Some participants have provided hints regarding the equations to use, suggesting the addition of rotational and translational kinetic energy. However, there is no explicit consensus on the final form of the equation, and further exploration of the problem is ongoing.

Contextual Notes

One participant raises a follow-up question regarding the scenario where the system is released from rest, indicating a potential shift in focus to the dynamics of the system as the weight descends. There is also mention of a specific value for the constant k, which may influence the calculations.

Momentum09
Messages
69
Reaction score
0

Homework Statement



Consider a circular wheel with a mass m, and a radius R. The moment of inertia about the center of the wheel is I = kmR^2, where k is a constant in the range between 0.5<k<1.0. A rope wraps around the wheel. A weight of mass 2m is attached to the end of this rope. At some moment, the weight is falling with a speed v. The total kinetic energy K of the system at this moment is given by what mathematical equation?

Homework Equations



K = 1/2 mv^2

The Attempt at a Solution



I know that the mass of the wheel will have to be considered to find the final kinetic energy...can someone please give me a hint what to do next?
 
Physics news on Phys.org
Use E_{k(rotational)} = \frac{1}{2} I \omega^2, then add the translational kinetic energy term to it. This would give the total kinetic energy. Energy terms in classsical mechanics are hardly ever multiplied or divided, so what's left to do is add or take away. In this case, since it's a total one wants, one adds.
 
Last edited:
thank you so much!
 
V=rw. Net T=T(rotational) + T(translational)
 
How about this?? It's the second part to the question...

Assume that k=1/2

QUESTION...If this system is released from rest, find the speed, v, at the moment when the weight has descended a vertical distance h. Any help would be nice.

Thanks
 
Momentum09 said:

Homework Statement



Consider a circular wheel with a mass m, and a radius R. The moment of inertia about the center of the wheel is I = kmR^2, where k is a constant in the range between 0.5<k<1.0. A rope wraps around the wheel. A weight of mass 2m is attached to the end of this rope. At some moment, the weight is falling with a speed v. The total kinetic energy K of the system at this moment is given by what mathematical equation?

Homework Equations



K = 1/2 mv^2

The Attempt at a Solution



I know that the mass of the wheel will have to be considered to find the final kinetic energy...can someone please give me a hint what to do next?

obviously your relevant equations 2 are incomplete, otherwise you would have your answer... what other relevant equations are there?
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
3K
Replies
46
Views
5K
Replies
4
Views
1K
  • · Replies 4 ·
Replies
4
Views
989
Replies
13
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
8
Views
14K
Replies
19
Views
3K