Presentation is loading. Please wait.

Presentation is loading. Please wait.

Conservation of Angular Momentum C13, C14. Basic Definitions… Torque (finally we get some direction!) Use the Right-Hand-Rule to determine the direction.

Similar presentations


Presentation on theme: "Conservation of Angular Momentum C13, C14. Basic Definitions… Torque (finally we get some direction!) Use the Right-Hand-Rule to determine the direction."— Presentation transcript:

1 Conservation of Angular Momentum C13, C14

2 Basic Definitions… Torque (finally we get some direction!) Use the Right-Hand-Rule to determine the direction of Torque. Curl the fingers of your right hand in the same direction that the object spins - your thumb points in the direction of the angular velocity, angular momentum, torque, acceleration, displacement …. Use VPython as a “vector calculator”!

3 Basic Definitions… Angular Momentum Note the fundamental link to the linear world in this form of the expression for angular momentum

4 In other words... Angular Momentum can be thought of in many different ways: These all inter-relate and each equation illustrates an aspect of this fundamental idea

5 Conservation of Angular Momentum Just as a moving object has linear momentum - a spinning object possesses angular momentum. As long as there are no external torques and the object is in an isolated system, angular momentum is conserved.

6 Examples of Conservation of Angular Momentum The figure skater – just Physics? Watch for the relationship between: –Arm movement and rotational speed –Rotational speed and vertical stability

7 Examples of Conservation of Angular Momentum The following applet can be used to illustrate conservation of L Neutron stars and PULSARS are nature’s version of the previous two examples! PULSARS

8 Angular Momentum and Precession What happens if we try to spin an object that is already spinning? Answer: depending how we do it the result can be counter- intuitive Go to VPython simulation

9 Digging Deeper – the math behind precession The slow rotation of a spinning wheel, suspended at only one point is an example of precession. We can easily determine the precession rate:

10 re-arrange to give… Example: a 1 kg bicycle wheel of radius 30 cm and spinning at 2 rev/s is suspended from a point 4 cm from the center of the wheel. What is the precession rate?

11 Important application - MRI

12


Download ppt "Conservation of Angular Momentum C13, C14. Basic Definitions… Torque (finally we get some direction!) Use the Right-Hand-Rule to determine the direction."

Similar presentations


Ads by Google