1 / 5

PHY221 Ch18: Rotational Statics II

PHY221 Ch18: Rotational Statics II. Applications: Examples: ladder and Box in truck Stability of object w/respect to gravity and CM location. PHY221 Ch18: Rotational Statics II. Examples. Example: Ladder of length L. Static  needed? Assume no friction on vertical wall. .

menora
Download Presentation

PHY221 Ch18: Rotational Statics II

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PHY221 Ch18: Rotational Statics II Applications: Examples: ladder and Box in truck Stability of object w/respect to gravity and CM location

  2. PHY221 Ch18: Rotational Statics II Examples Example: Ladder of length L. Static  needed? Assume no friction on vertical wall. 

  3. PHY221 Ch18: Rotational Statics Examples • Example: Box in truck • Truck accelerates forward • Assume friction large enough so box doesn’t slide • But: it can tip! • Problem: what is the max acc. for no tipping? Draw picture with forces and choose axes (remember that accel. not zero) Force equation: Torque equation: (be careful about choosing O; not all points valid!)

  4. PHY221 Ch18: Rotational Statics Stability • Stability of equilibrium and torque: • Equilibrium requires net force and net torque equal to zero on object • But some configurations are stable and some unstable. • Consider following 2 configs of a red bar that can freely rotate around a pivot pt O: Forces applied? Net force? Net torque? Let’s look at what happens when the red bar is pushed slightly from equil? Force point of view: Torque point of view: Relation of stability of equil. to potential energy:

  5. PHY221 Ch18: Rotational Statics II Stability Application: Stability and CM position for object resting on surfaces (and relation to potential energy change) • Look at tipping around O (clearly the interesting point here) • Assume object barely off surface (so that N is all applied at O) and study motion: Now let’s relate to what happens to pot energy. On the left the rotation around O would increase or decrease the pot energy? On the right the rotation around O would increase or decrease the pot energy?

More Related