Determine the magnitude and coordinate direction angles of the resultant couple moment.

The gears are subjected to the couple moments
shown. Determine the magnitude and coordinate direction
angles of the resultant couple moment.

[SJFredrick]

Hi dax, thank-you for your videos! Really late notice but could you please do, #10-44, #10-45 and #10-47 from the statics 14th edition?
Preparing for an exam tomorrow and solutions to these would be really helpful!

[KidsandKittens]

Need your guidance on this please:
From 37 seconds to 53 seconds you draw vector directions for the 3 components of M1. How are those of us who are novices to know which direction those component vectors go, when we haven’t yet done the math? In previous problems we always determined whether a component was positive or negative based on it’s location on the corresponding axis, such as an x component would be negative if it was on the negative side of the x-axis. Wouldn’t it be safer for a beginner to use that method rather than guessing the direction of component vectors right at the beginning of the problem? The problem works out to the same answer, all except for the z component being -13.7, when trying to find the corresponding coordinate direction angle.

While doing the math for the problem, I would have called 13.7 positive because it is in the positive direction of the z-axis. However, the correct coordinate direction angle cannot be found with 13.7 as positive. Why is that? And how can I assign the correct positive or negative signs to a component vector when I am too inexperienced to guess what sign (direction) the component vectors are in at the very beginning of doing a problem?

[dariocosemans]

Hi there,


The excersise went well, but I was wondering: What is the rotation of the resultant couple moment? Is it possible to get it by looking to the cartesian coördinates of the resultant moment?

[johnan]

Problem 5.63 Due to an unequal distribution of fuel in the wing tanks, the centers of gravity for the airplane fuselage A and wings B and C are located as shown. If these components have weights WA = 41000 lb, WB=8000lb, and WC=6000lb, determine the normal reactions of the wheels D, E, and F on the ground.