본문/내용
Chapter 1
Problems 1-1 through 1-4 are for student research. 1-5
Impending motion to left E
1 f A
1 f B G Fcr F
cr
D
C
Facc
Consider force F at G, reactions at B and D. Extend lines of action for fully-developed friction D E and B E to ?nd the point of concurrency at E for impending motion to the left. The critical angle is θcr . Resolve force F into components Facc and Fcr . Facc is related to mass and acceleration. Pin accelerates to left for any angle 0 < θ < θcr . When θ > θcr , no magnitude of F will move the pin.
Impending motion to right E E
1 f A d D
1 f B G Fcr C
cr
F Facc
Consider force F at G, reactions at A and C. Extend lines of action for fully-developed friction AE and C E to ?nd the point of concurrency at E for impending motion to the left. The critical angle is θcr . Resolve force F into components Facc and Fcr . Facc is related to mass and acceleration. Pin accelerates to right for any angle 0 < θ < θcr . When θ > θcr , no