Block A supports a pipe column and rests as shown on wedge B.Knowing that the coefficient of static friction at all surfaces of contact is 0.25 and that θ = 45°, determine the smallest force P required to raise block A.

Step: 1

Calculate the friction angle by using the following relation:

Substitute 0.25 for .

Step: 2

Draw the free body diagram of the block A.

Here, are the reaction forces on block A.

Step: 3

Draw the force triangle for block A.

Step: 4

Apply the law of sine and solve.

Substitute for and for .

Step: 5

Draw the free body diagram of wedge B.

Step: 6

Draw the force triangle for block B.

Step: 7

Calculate the smallest force P.

Apply the law of sines and solve.

Substitute for and for .

Therefore, the smallest force required to raise block A is .

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