Rotational Kinetic Energy - Clarification on what I need to solve for

In summary, a solid cylinder with a mass of 13 kg and radius of 0.33m undergoes an angular acceleration of 5 rad/s^2 for 18 seconds, rotating about its center axis. The question asks to find the kinetic energy at the end of 1 second, assuming there is no translation. Using the formula KE = 1/2mv^2 + 1/2 I*w^2, the rotational kinetic energy is found to be 31.85.
  • #1
grandprix
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Homework Statement


A wheel (solid cylinder), mass of 13 kg and radius of 0.33m is initially at rest. The wheel undergoes an angular acceleration of 5 rad/s^2 for 18 seconds, rotating about its center axis (no translation). Find the Kinetic energy of the wheel at the end of the 1 seconds.

Homework Equations


KE = 1/2mv^2 + 1/2 I*w^2


The Attempt at a Solution


Okay so I was a little confused on whether I am finding the Total KE, or just th rotational KE.

If I were solving for total, KE = 1/2mv^2 + 1/2 I*w^2
First I need to solve for v, which I got to be 29.7, by employing the formula v=wr

I solved the equation for total KE and got 5765.438, where 5733.58 = 1/2mv^2 and 31.85 = is equal to 1/2 I W^2.

If I just needed to find the KE rot, then the answer would be 31.85.
 
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  • #2
grandprix said:

Homework Statement


A wheel (solid cylinder), mass of 13 kg and radius of 0.33m is initially at rest. The wheel undergoes an angular acceleration of 5 rad/s^2 for 18 seconds, rotating about its center axis (no translation). Find the Kinetic energy of the wheel at the end of the 1 seconds
The question does say no translation, so I assume you just need to get the rotational kinetic energy.

EDIT: How did you get so little rotational kinetic energy? Did you apply 1/2Iw2 correctly?
 
  • #3
Thank you ! I may have done that wrong. I will chck it over
 

FAQ: Rotational Kinetic Energy - Clarification on what I need to solve for

What is rotational kinetic energy?

Rotational kinetic energy refers to the energy an object possesses due to its rotational motion. It is the product of an object's moment of inertia and its angular velocity squared.

How is rotational kinetic energy different from linear kinetic energy?

Rotational kinetic energy is the energy an object possesses due to its rotational motion, while linear kinetic energy is the energy an object possesses due to its linear or straight-line motion. They are calculated using different equations and have different units of measurement.

What factors affect the rotational kinetic energy of an object?

The rotational kinetic energy of an object is affected by its moment of inertia and its angular velocity. A larger moment of inertia or higher angular velocity will result in a greater rotational kinetic energy.

How do I calculate the rotational kinetic energy of an object?

The formula for calculating rotational kinetic energy is E = 1/2 * I * ω^2, where E is the rotational kinetic energy, I is the moment of inertia, and ω is the angular velocity. Make sure to use consistent units for these variables.

What is the relationship between rotational kinetic energy and work?

Rotational kinetic energy is a form of energy and can be converted into other forms of energy, such as work. The work done on an object to change its rotational kinetic energy is equal to the change in rotational kinetic energy. This can be calculated using the work-energy theorem, W = ΔE.

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