A 10-Ib block B rests as shown on a 20-1b bracket A. The coefficients of friction are
(a)
Maximum weight of block C if block B is not to slide on bracket A.
Answer to Problem 12.31P
Maximum weight of block C is
Explanation of Solution
Given:
Concept used:
Kinematics :
Let
Let
Note that
The cable length is fixed.
Differentiating and noting that
Here.
Kinetics :
Let
The free body diagrams are shown here:
Bracket A:
Block B:
Block C:
Bracket A:
Block B:
Block C:
Adding Eqs. (2). (3) and (4) and transposing.
Subtracting Eq. (4) from Eq. (3) and transposing.
No slip between A and B.
From Eq. (1).
From Eq. (5).
For impeding slip.
Substituting into Eq. (6).
Solving for
(b)
Accelerations of A, B, and C, if the weight of block C is 10 percent larger than the result of part a.
Answer to Problem 12.31P
Accelerations of A. B and C:
Explanation of Solution
Given:
Since slip is occurring.
Eq. (6) becomes.
Or:
With given data. Eq. (5) becomes
Solving Eqs. (1). (7). and (8) gives
So,
And,
And
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Chapter 12 Solutions
Vector Mechanics For Engineers
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- International Edition---engineering Mechanics: St...Mechanical EngineeringISBN:9781305501607Author:Andrew Pytel And Jaan KiusalaasPublisher:CENGAGE L