Angular Velocity and Kinetic Energy Problem?

In summary, the angular velocity of the wheel is 0.625 rad/sec^2 and the kinetic energy after 10 seconds is 312 J. However, more data (such as the radius of the wheel and the distance from the center where the force is applied) is needed to solve the problem accurately. The question's language is also a bit confusing, but a general formula of \omega=0.625t can be used to find the angular velocity at any given time.
  • #1
keylostman
14
0
A wheel turns with a moment of intertia of 16.0kg m^2 and has 10m N applied to it. if it starts from rest calculate the angular velocity. Also what is the kinetic energy 10seconds later?

The wheels angular velocity i used T=IA, and solved for Angular velocity solving for a i got .625rad/sec^2 . For knetic energy .625rad/sec^2 i get to 6.25rad/sec. then i take 1/2IW^2, and i get 312 J

Is my work correct ? If i made a mistake , can you please tell me where ?
 
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  • #2
A wheel turns with a moment of intertia of 16.0kg m^2 and has 10m N applied to it. if it starts from rest calculate the angular velocity. Also what is the kinetic energy 10seconds later?

Hi,:smile:

If I'm not wrong (which I am most of the time), you need more data (radius of wheel and distance from the centre where the 10mN force is applied) to solve this problem :confused:
 
  • #3
keylostman said:
A wheel turns with a moment of intertia of 16.0kg m^2 and has 10m N applied to it. if it starts from rest calculate the angular velocity. Also what is the kinetic energy 10seconds later?

The wheels angular velocity i used T=IA, and solved for Angular velocity solving for a i got .625rad/sec^2 . For knetic energy .625rad/sec^2 i get to 6.25rad/sec. then i take 1/2IW^2, and i get 312 J

Is my work correct ? If i made a mistake , can you please tell me where ?
It looks OK to me, assuming you meant to find the angular acceleration (not the angular velocity). To find the angular velocity, you'd need to know at what time.

Google_Spider said:
If I'm not wrong (which I am most of the time), you need more data (radius of wheel and distance from the centre where the 10mN force is applied) to solve this problem
10 m N (better: 10 N-m) is a torque, not a force.
 
  • #4
i meant the angular velocity, i wanted to find, how would i find it ?
 
  • #5
keylostman said:
i meant the angular velocity, i wanted to find, how would i find it ?
Depends on when. You found the angular velocity after 10 s, which you needed to calculate the KE.

Did you present the problem exactly as it was given to you?
 
  • #6
Yes Doc, its correct. THe problem is copied right
 
  • #7
Doc Al said:
10 m N (better: 10 N-m) is a torque, not a force.

OK, I thought it was 10 milli Newton force.

May I suggest using [tex]\omega=\omega_o+\alpha t[/tex]
 
  • #8
and KE =[tex]\frac{I{\omega}^2}{2}[/tex]
 
  • #9
keylostman said:
if it starts from rest calculate the angular velocity. Also what is the kinetic energy 10seconds later?
This is slightly ambiguous. Do they mean: 10 seconds later, calculate the angular velocity and the kinetic energy. (If so, then you did calculate the angular velocity.)

In order to calculate the velocity and KE, you must first calculate the angular acceleration. Which you did, even though you incorrectly called it angular velocity.

Google_Spider said:
OK, I thought it was 10 milli Newton force.
You never know! :wink: That's why I asked if the problem was presented exactly as given.
 
  • #10
Google_Spider said:
OK, I thought it was 10 milli Newton force.

May I suggest using [tex]\omega=\omega_o+\alpha t[/tex]

For angular velocity, i don't know the time, the time is implied toward the 2nd part of question
 
  • #11
keylostman said:
For angular velocity, i don't know the time, the time is implied toward the 2nd part of question

Yeah. The question's language is a bit confusing. But I feel like they want angular velocity at 10 seconds, though they don't mention it.

Why not give them a general answer
[tex]\omega=0.625t[/tex]

They can plug in whatever t they want and get the result :wink:
 
  • #12
Now you see the torture i go through to understand problems lol. All his questions are worded badly, must be cause he is from another Country heh
 
  • #13
keylostman said:
A wheel turns with a moment of intertia of 16.0kg m^2 and has 10m N applied to it. if it starts from rest calculate the angular velocity. Also what is the kinetic energy 10seconds later?

The wheels angular velocity i used T=IA, and solved for Angular velocity solving for a i got .625rad/sec^2 . For knetic energy .625rad/sec^2 i get to 6.25rad/sec. then i take 1/2IW^2, and i get 312 J

Is my work correct ? If i made a mistake , can you please tell me where ?

Thats correct mate.
 

What is angular velocity?

Angular velocity is a measure of the rate of change of angular displacement with respect to time. It is commonly represented by the symbol ω (omega) and is measured in radians per second.

What is kinetic energy?

Kinetic energy is the energy an object possesses due to its motion. It is dependent on the mass and velocity of the object and is represented by the equation KE = ½mv², where m is the mass and v is the velocity.

How are angular velocity and kinetic energy related?

Angular velocity and kinetic energy are directly proportional. This means that as the angular velocity of an object increases, so does its kinetic energy. This relationship can be seen in the equation KE = ½Iω², where I is the moment of inertia and ω is the angular velocity.

What is the importance of solving problems involving angular velocity and kinetic energy?

Solving problems involving angular velocity and kinetic energy can help us understand the behavior of rotating objects and how energy is transferred and conserved in these systems. This knowledge is essential in many fields such as engineering, physics, and mechanics.

What are some real-life applications of angular velocity and kinetic energy?

Angular velocity and kinetic energy are important in various real-life applications, such as the motion of planets and other celestial bodies in space, the rotation of gears in machinery, and the movement of vehicles such as cars and airplanes. They are also crucial in sports, such as figuring skating and gymnastics, where angular velocity and kinetic energy play a significant role in the performance of athletes.

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