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o Chapter 06, Problem 027 Body A in the figure weighs 95 n, and body B weighs 72

ID: 1790516 • Letter: O

Question

o Chapter 06, Problem 027 Body A in the figure weighs 95 n, and body B weighs 72 N. The coefficients of friction between A and the incline are us-o.4s and positive direction of an x axis be up the incline. What is the acceleration of A if A is initially (a) at rest, (b) 44. Let the moving up the indline, and (c) moving down the incline? 0.26. A gle e massless pulley (a) Number (b) Number (e) Number will learn while you earn points based on the Point Potential Policy set by your instructor Question Attempts: O of 2 used SAVE FOR LATER Earn Maximum Points available only if you answer this question correctly in your first attempt. by MapleNet

Explanation / Answer


Given data

Body A weighs , w1 = 95 N

Body B weighs , w2 = 72 N

Coefficients of friction between A and the incline are

s = 0.45 and k = 0.26

Angle = 44 degree

(a) At rest the acceleration of A is zero.

(b) A is moving up the incline, then net force on A is

m1*a = T - k*N - w1*sin44 ------------1

And net force on B is

m2*a = w2 - T ------------2

Using eq 1 and eq 2

m2*a = w2 - (m1*a + k *N + w1*sin44)

a = w2 - k* w1 *cos44 - w1* sin44 / (m1 + m2)  

a = 72 N - 0.26 *95 N * 0.7194 - 95 N * 0.6946 / (95 N + 72 N ) / 9.8 m/s^2

a = - 0.689 m/s^2 = 0.689 m/s^2 (-j) (Downwards)

(c) A is moving down the incline, then net force on A is

m1* a = w1* sin44 - T - k* w1* cos44 ---------------3

And net force on B is

m2* a = T - w2 ----------------4

Using eq 3 and eq 4

m2 *a = - m1*a + w1 *sin44 - k* w1* cos44 - w2

a = 95 N * 0.6946 - 0.26 *95 N *0.7194 - 72 N / (95 N + 72N ) / 9.8 m/s^2

a = -1.395 m/s^2 = 1.39 m/s^2 (-j) ( Downwards )