# It is known that a force with a moment of 960 N · m about D is required to straighten the fence post CD. If the capacity of winch puller AB is 2400 N, determine the minimum value of distance d to create the specified moment about Point D.

Question-AnswerCategory: Engineering MechanicsIt is known that a force with a moment of 960 N · m about D is required to straighten the fence post CD. If the capacity of winch puller AB is 2400 N, determine the minimum value of distance d to create the specified moment about Point D.

It is known that a force with a moment of 960 N · m about D is required to straighten the fence post CD. If the capacity of winch puller AB is 2400 N, determine the minimum value of distance d to create the specified moment about Point D.

Step: 1

Draw the free-body diagram of the fence post:

Step: 2

From the geometry of the figure, state as follows:

Here, the angle between ED and EC is  and the distance between E and D is.

Step: 3

Consider the equilibrium of moments about point .

Here, the moment acting at D is  and the maximum tension in cable BC is .
Substitute   and  in the above equation,

Step: 4

Solve the above quadratic equation for the value of d.

From the above data, the value of d should not be negative in sign. Hence, the value is.
Therefore, the minimum value of distance d to create a specified moment about the point D is .