ch06-p100 - value tells us that our initial assumption...

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Unformatted text preview: value tells us that our initial assumption about the direction of f is incorrect in this case. Thus, the answer is: f s = 32 N up. (f) In this case, P = 18 N downward. The above equation (but with P replaced with P ) with the same assumptions as in part (a), leads to f = (18 22) N = 40 N, which is larger (in absolute value) than f s , max , -- invalidating our assumptions. Therefore, we take f = f k and a 0 in the above equation; if we wished to find the value of a we would find it to be negative, as we should expect. The answer is: f k = 23 N up. (g) The block moves up the wall in case (d) where a > 0. (h) The block moves down the wall in case (f) where a < 0. (i) The frictional force f s is directed down in cases (a), (c) and (d). 100. Analysis of forces in the horizontal direction (where there can be no acceleration) leads to the conclusion that F = F N ; the magnitude of the normal force is 60 N. The maximum possible static friction force is therefore...
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This note was uploaded on 05/17/2011 for the course PHY 2049 taught by Professor Any during the Spring '08 term at University of Florida.

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