Question

The same couple moment of 160 lb⋅ftlb⋅ft is required to open the hatch door, independent of where the couple's forces are applied. If the forces are applied at points C and D, what force magnitude FFF is required to open the hatch door?

Answer 1

F = 88.88[lb-f]

Step-by-step explanation:

To solve this problem, we must first look at the attached image.

Another important data that is needed to solve the problem is the distance from the Centre O to points C and D. The distance is 0.9 [ft].

Then we do a sum of moments around Point O and it equals zero.

`SM_(O) =0\\F*0.9+F*0.9-160=0\\2*F*0.9=160\\F=88.88[lb-f]`

Therefrore the couple of forces needed are 88.88[lb-f]