Time for a flywheel to stop, given moment of inertia + a tangential force

In summary, the conversation revolved around solving for the time in minutes for a flywheel with a moment of inertia of 0.5kgm^2, diameter 0.5m, and a tangential frictional force of 1000N to stop rotating at 1000rpm. The conversation included equations for torque and angular velocity, and both individuals arrived at an answer of pi/30 squared minutes. One person expressed confusion over the small answer, while the other suggested double-checking the working and seeking advice.
  • #1
Roomie
29
0

Homework Statement



A flywheel has a moment of inertia of 0.5kgm^2, diameter 0.5m and is rotating at 1000rpm.
A tangential frictional force of 1000N is applied to its rim.
Calculate the time IN MINUTES for the flywheel to stop.

Homework Equations



None given, I assume:

Torque = I*alpha
Angular Velocity = Angular Velocity at t=0 + alpha*t

The Attempt at a Solution



Here is my attempt:
[PLAIN]http://img600.imageshack.us/img600/6962/scan2.png

You can see I get to a final answer, but it doesn't make sense in my opinion since the question asked for it expressed in minutes, why would they do that if it was going to be such a tiny answer?

If someone could check my working and offer any advice it would be much appreciated, thanks!
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
Hello roomie.I got an answer of pi/30 squared minutes which is what you got.
 

1. How do you calculate the moment of inertia for a flywheel?

The moment of inertia for a flywheel can be calculated by multiplying the mass of the flywheel by the square of its radius and its rotational speed.

2. What is the role of a tangential force in determining the time for a flywheel to stop?

A tangential force acts on a flywheel in the direction of its rotation and is responsible for slowing down the flywheel's rotational speed. The greater the tangential force, the faster the flywheel will stop.

3. Can you provide an equation for calculating the time for a flywheel to stop?

Yes, the equation for calculating the time for a flywheel to stop is: t = (2 x pi x I)/F, where t is time, I is moment of inertia, and F is the tangential force.

4. How does the moment of inertia affect the time for a flywheel to stop?

The moment of inertia is a measure of an object's resistance to changes in its rotational motion. The higher the moment of inertia for a flywheel, the longer it will take for the flywheel to stop due to its increased resistance to changes in speed.

5. Is there a way to decrease the time for a flywheel to stop?

Yes, there are a few ways to decrease the time for a flywheel to stop. One way is to increase the tangential force acting on the flywheel. Another way is to decrease the moment of inertia by reducing the mass or radius of the flywheel. Additionally, reducing friction in the flywheel's bearings can also decrease the time for it to stop.

Similar threads

Gearbox and flywheel question, How to calculate input torque
    • Engineering and Comp Sci Homework Help
Replies
6
Views
3K
Calculating Stopping Time for a Flywheel & Disk Brake System
    • Engineering and Comp Sci Homework Help
Replies
10
Views
4K
Input Power against time graph - Flywheel from rest to 300rpm
    • Engineering and Comp Sci Homework Help
Replies
18
Views
4K
Flywheel and Gearbox Coupling Help
    • Engineering and Comp Sci Homework Help
Replies
3
Views
3K
How to use Moments of Inertia to find Max Acceleration (sportbike pre-wheelie)
    • Engineering and Comp Sci Homework Help
Replies
9
Views
7K
Mass suspended from rotating flywheel
    • Engineering and Comp Sci Homework Help
Replies
6
Views
3K
I I'm calculating more energy out than I put in
    • Classical Physics
2
Replies
61
Views
1K
Flywheel Inertia Design for Piston Engine
    • Engineering and Comp Sci Homework Help
Replies
2
Views
3K
Spinning up a flywheel with a motor
    • Mechanics
2
Replies
43
Views
4K
Oscillating Hydrofoil Frequency
    • Engineering and Comp Sci Homework Help
Replies
1
Views
1K

Hot Threads

Recent Insights

Back
Top