# Lec24 - L e c t u r e 2 4 W e d n e s d a y 1 / 2 1 / 9 C h...

This preview shows pages 1–5. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: L e c t u r e 2 4 W e d n e s d a y 1 / 2 1 / 9 C h a p t e r 1 1 : 1- 3 S t a t i c s B o d i e s i n S t a t i c E q u i l i b r i u m S t a t i c : t h e b o d y i s a t r e s t : E q u i l i b r i u m :-- T h e n e t f o r c e o n t h e b o d y i s z e r o :-- T h e n e t t o r q u e o n t h e b o d y i s z e r o : C e n t e r o f g r a v i t y o f a b o d y-- T h e n e t f o r c e a n d t h e n e t t o r q u e d u e t o g r a v i t y b o t h a c t o n t h e c e n t e r o f g r a v i t y , w h i c h i s t h e c e n t e r o f m a s s v c m = , = F n e t e x t = n e t e x t = T h e g e n e r a l c o n d i t i o n t h a t t h e b e a m i s b a l a n c e d ( r e m a i n s a t r e s t w h e n r e l e a s e d ) i s _ _ _ . H i n t : s e t n e t z = a b o u t p o i n t O f o r t h e b e a m . Q u e s t i o n 1 . m 1 L 2 = m 2 L 1 2 . m 1 2 L 1 = m 2 2 L 2 3 . m 1 L 1 = m 2 L 2 4 . L 1 = L 2 S t a t i c e q u i l i b r i u m : F n e t y = n w 1 w 2 = , w h i c h g i v e s n = ( m 1 + m 2 ) g . S t a t i c e q u i l i b r i u m : n e t z = T h e t o r q u e d u e t o m 1 i s 1 z = r 1 w 1 = L 1 m 1 g . T h e t o r q u e d u e t o m 2 i s 2 z = r 2 w 2 = L 2 m 2 g . T h e n n e t z = 1 z + 2 z = g ( m 1 L 1 m 2 L 2 ) = . T h i s g i v e s m 1 L 1 = m 2 L 2 . T h i s i s k n o w n a s t h e &quot; l e v e r r u l e &quot; . S o l u t i o n T h e d i s t a n c e L m f r o m m a s s m t o t h e f u l c r u m i s _ _ m . 1 . . 5 2 . . 6 3 . . 7 4 . . 8 A b e a m o f m a s s M = 8 . k g a n d l e n g t h L = 2 . m h a s a m a s s m = 2 . k g o n t h e l e f t e n d a s s h o w n . T h e b e a m i s b a l a n c e d o n a f u l c r u m . Q u e s t i o n S o l u t i o n G r a v i t y a c t s o n t h e c e n t e r o f m a s s w h i c h i s a t a d i s t a n c e L / 2 f r o m t h e l e f t e n d . T h e n u s i n g t h e l e v e r r u l e w e g e t m L m = M L 2 L m . S o l v i n g f o r L m g i v e s L m = M L / 2 M + m = ( 8 k g ) ( 2 m ) / 2 8 k g + 2 k g = . 8 m . A t t h e m o m e n t t h e r o d i s r e l e a s e d , t h e m a g n i t u...
View Full Document

## This note was uploaded on 10/21/2010 for the course PHYS 221 taught by Professor Herrera-siklody during the Fall '08 term at Iowa State.

### Page1 / 12

Lec24 - L e c t u r e 2 4 W e d n e s d a y 1 / 2 1 / 9 C h...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online