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If the weight of the beam is not neglected, you then would treat that weight as a uniform load across the beam. This can be seen in this video: ruclips.net/video/zE5Gr9MuSfI/видео.html In this video, the uniform load is the 2 k/ft. Now, if you only knew the beam weighed 5 lbs for example, then you would have to divide that 5 lbs by the entire length of the beam (13 ft in total) to turn it into a constant uniform load across the beam. Units are important here. Thus, the uniform load would be 5 lbs/13 ft = 0.385 lb/ft. I hope this helps and answers your question.

In reality, yes there are x and y components at point D just like C. However, in this problem, we only need to "look at" member ACB to calculate what the problem is asking for us to find. If you wanted to determine the x and y components at point D, use the cable tension force T and point D to determine the Dx and Dy reactions by using equilibrium in the X and Y directions. I hope this helps and answers your question.

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No problem!

Since this problem is in US Customary Units, we do not include the acceleration of gravity on weights in units of force such as pounds (lbs), kips (k) or tons. In the SI system, we need to include/multiply by the acceleration of gravity on masses such as kilograms (kg) to convert these masses into forces, which would be Newtons. In US Customary Units, if we were given a mass, which would be in units of slugs, then we would have to multiply by the acceleration of gravity. So, in short, when in force units do not multiply by the acceleration of gravity. I hope this helps.

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You're welcome!

I'm assuming you are asking about the summation of moments about point A. At this location, there are only 3 forces which have moment/rotation about Point A. Since Dx is the only force that we do not know at this time, we can solve for it as shown in the video. Working out the rotations and math, the Dx value must be 73.6 N to the left to create equilibrium. I hope this helps.

Thank you!

360/2 ie 180- ( 25*2) i guessed but it's a bit different here! Did you got the answer??

This was done because we know the parallelogram contains 360 degrees total (as do all 4 sided shapes). We know from the problem statement that this parallelogram contains a 25 degree angle. Since it is a parallelogram, the angles which are opposite locations are of equal value, thus there are 2 angles of 25 degrees. Thus, in order to determine what amount of angles remain in the shape, we take 360 - (2)(25). I hope this helps.

I'm assuming you are asking about Point B. This point is on the raft at the location where the two cables connect. If this is not what you were asking, please let me know.

Summation of moments is the process of adding/substracting moments from one another to determine the total/remaining moment on the member. I hope this explanation helps.

Do you offer any tutoring services?

Awesome! Glad I could help!

This problem came "Statics and Mechanics of Materials" by Beer, Johnston, DeWolf, and Mazurek. McGraw Hill is the publisher.

Thanks!

Thanks! You are welcome!

This problem came "Statics and Mechanics of Materials" by Beer, Johnston, DeWolf, and Mazurek. McGraw Hill is the publisher.

For this problem, we need to determine the range of P which will keep each cable in tension, thus a positive value based on the free body diagram. Once the cable force becomes zero or negative (meaning it will turn to compression rather than tension), the limit of the P force for that cable has been found. This is why we set the cable force to be zero, since we want the absolute limits for P. For example at the beginning, when we set Fac to be zero, this results in the P value which no longer creates tension in cable Fac, thus this is one of our limits for the applied P force. Then you will repeat this process for the other cable force to find the other limit of P. I hope this explanation helps.

Glad it helped!

Thank you for the kind words! I'm so happy that the video helped you! Have a great day!

Great! Happy to help!

You're welcome!

You're welcome!

Sorry for the late reply, but we know the summation of the forces in the x direction must be zero since the resultant is 100% vertical (as stated in the problem statement). Since the resultant force for a 2D system is R = sqrt[ (summation of Fx)^2 + (summation of Fy)^2], including the statement of R being 100% vertical, then by the equation R = summation of Fy forces, thus summation of Fx forces = 0. I hope this explanation helps.

Glad it was helpful!

Wow, thanks!