Question

Two blocks A and B have a weight of 9 lb and 6 lb, respectively, They are resting on the incline for which the coefficients of static friction are p = 0.16 and B = 0.26. Determine the angle which will cause motion of one of the blocks. What is the friction force under each of the blocks when this occurs? The spring has a stiffness of k = 2 lb/ft and is originally unstretched (Figure 1) Part A Determine the smallest angle which will cause motion of one of the blocks. Express your answer to three significant figures and include the appropriate units. ? 8 = Value Units Figure 1 of 1 Submit Previous Answers Request Answer * Incorrect; Try Again; 5 attempts remaining Part B k-2 lb/ft Determine is the friction force under the block A at this angle. Express your answer to three significant figures and include the appropriate units. MA ? FA- Value Units

Answer 1

FBD (A) (B) Esp A NB ANA A for(s), fp = (F) (alosime) valblos o Closino Esp 6lbCoso W-Glo? W =(616) MB=0.26 MA=0016

surface Equilibrium equation along A F8 +(6) - 9 Sin D = 0 Esp kn = (2x) 0.16 C aut (Max 9 Caso ) - 9 Sino -0) 2n=9 sino-1.44 Cos o öll -føpt (fs)- 6 Sino = 0 - 2x +(0.26x6 Coso ) - 6 Sin 0 = 6 -0) an= 1.56 Cos 0-6 Sino Equate (1) and (2) = 1.56 Coso-6Sino 9 Sino-1:44 . Caso 11. 3° 1.412 lb Part A Calculate (Fs)a and (Fs) B Part B: (EDA = MA NA = 0.168 9 Cos 11:30 pard C: My NB= 0.26 X 6 Casil 3° 1. 5297 lb lu