For Question 1-6, consider the 20 lb wheel A and 30 lb block C sitting on the horizontal surface. A cord wrapped around the wheel is attached to the top of the block. The static and kinetic coefficients of friction between the surface and the wheel are μS,B = 0.25 and μK,B = 0.2, respectively. The static and kinetic coefficients of friction between the surface and the block are μS,D = 0.3 and μK,D = 0.24, respectively. We would like to determine the largest vertical force P that can be applied to the wheel without anything moving. In this problem, we have determined that there are three cases of possible impending motion to consider:
(1) Wheel A could slip at B and start to move to the right,
(2) Block C could slip at D and start to move to the left, and
(3) Block C could tip to the left.
Which of the following statements about solving this problem is correct?
Group of answer choices
a) By initial inspection, you can determine which is the controlling case, allowing you to analyze only that case.
b) By assuming that all three cases occur at the same time, it is possible to determine the limiting force by solving the problem once.
c) Each possible case needs to be considered as occurring by itself as none require another to occur at the same time.