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# Help With Statics!?

Topic: Help With Statics!?
July 20, 2019 / By Bab
Question: http://session.masteringengineering.com/problemAsset/1521345/6/Hibbler.ch3.p29.jpg Determine the maximum mass of the lamp that the cord system can support so that no single cord develops a tension exceeding 500 N. please explain how to do this!

## Best Answers: Help With Statics!?

Abra | 5 days ago
Apply Conditions of Equilibrium at joints C and D. since your problem requires no tension exceeds 500N in any cable, assume DE as 500N, because by inspection, it carries the greatest percentage of load distribution among cables. Consider Joint D. [ΣFy=0] W - DEsin30 = 0 W - 500sin30 = 0 W = 250 N <== Note that this value is tentative, you'll need to check the other cables.. checking for cable DC [ΣFx=0] DC - DEcos30 = 0 DC = 500cos30 DC = 433.0127019 N (still okay, not greater than 500N) Now consider Joint C to check for cables CA and CB [ΣFy=0] CA(4/5) - CBsin45 = 0.........................equation 1 [ΣFx=0] CA(3/5) + CBcos45 = 433.0127019......equation 2 solving simultaneously CA = 309.2947871 N (less than 500 N, ok!) CB = 349.9871061 N (less than 500 N, ok!) All cables did not exceed 500, therefore 250N (25.4841998 Kg) is the maximum weight the system can carry. Any weight above 250 N will cause failure of cable DE...
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Originally Answered: What do you do in a Statics/Dynamics class?
Like the other answers say, it is about Newtonian Mechanics. Both courses expand on the principle of the basic law of mechanics from physics 1. I took them both and here is my summary: Statics- The study of the mechanics of objects either in rest or at constant velocity. The class pretty much revolved around equilibrium of forces, (the net forces equal zero for a body). This class will make you work a bit and its not too difficult once you learn the concepts and do a little practice. Dynamics- The study of the mechanics of motion of objects. This class was pretty brutal and there will be quite a bit of formulas to go over. You WILL have to do a lot of practice and a lot of work to receive a good grade in this class. Unlike statics, dynamics will require you to manipulate several equations to find a useful solution to the problem In both classes (at University level) there is no group work. You will find this is the case at many Universities. If you do not receive an A in statics do not expect one in dynamics. Good luck with your choice.
Originally Answered: What do you do in a Statics/Dynamics class?
^haha I bet this guy's an engineer like me and while I say the same thing now, at the time those were pretty challenging esp. dynamics. depends a lot on your teacher though and whether he likes to give hard problems, because there is a very wide range of difficulty for statics/dynamics probs. having graduated, I still consider dynamics to be one of the hardest classes I ever took. having said that, if you cant get a B-B+ in statics you probably shouldnt go further into engineering.
Originally Answered: What do you do in a Statics/Dynamics class?
A statics/dynamics course will teach you about Newtonian mechanics. It is a physics course. You should probably expect labs done in groups. How hard it is to get an A depends on your abilities. Since neither you nor anyone else is capable of precisely describing those, it's impossible to say.

Sybald
Any statics problem begins with the following tenets: 1) The sum of the upward components must equal the weight 2) The horizontal components are constrained to be equal to one another. This means upward forces equal downward and are net zero, and horizontal forces balnce each out for a net force of zero also So write out summation equation with all the forces in the y direction summing up to zero, then write out summation of forces in the x direction and also set to zero. Be consistent in how oyu multiply an angle. If for angle q you use cos q for x direction , then you multiply the angle q by the sin q when calculating the y direction Start at the left of your problem and calculate the Summation of forces in the y direction for each point on the picture. Then do the same starting from the left and moe toward the right and only do summations of the forces in the x dirrection. Use zero on the other side of the equation when calculating the summations Here is a problem with tensions and a hanging mass that is similar to your problem and just lay out your problem following the same steps of summation as this one: http://hyperphysics.phy-astr.gsu.edu/hba... Here is another form of the same problem hooked to a wall: http://hyperphysics.phy-astr.gsu.edu/hba...
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