A small boat hangs from two davits, one of which is shown in the figure. It is k
ID: 1919979 • Letter: A
Question
A small boat hangs from two davits, one of which is shown in the figure. It is known that the moment about the y axis of the resultant force RA exerted on the davit at A must not exceed 139 lb-ft in absolute value. Determine the largest allowable tension in line ABAD when x = 7 ft.
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A small boat hangs from two davits, one of which is shown in the figure. It is known that the moment about the y axis of the resultant force RA exerted on the davit at A must not exceed 139 lb-ft in absolute value. Determine the largest allowable tension in line ABAD when x = 7 ft.Explanation / Answer
Moment of a force = r x F
= r.F.sin?.
So moment will be due to forces in either x or z direction.
There is no force in z direction and the only force acting in x direction is the horizontal
component of tension in string AD . Hence let maximum allowable tension be T.
139= T sina.3.(1) where a is the angle between AB and AD
139= T.(7/((7^2 + 8.25^2)^0.5)).3
T= 71.62 lb
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