Consider two similar triangles (same base to altitude ratio), one having a base of 15ft and another of 12ft. The altitude of a triangle having a base of 15ft is 60, and another of 12ft is unknown (let's say x). So, using ratio 12/x=15/60. Solving this will give x = 48.
Whenever we have a triangular shape load (uniformly varying load) the point of application of load will be L/3 from the bigger side (at the centroid of the triangle).
For uniformly varying load(UVL), the load will act at 1/3 of the total length of UVL from the larger side. 12 x 1/3 = 4 ft, larger side is B, hence 4ft from point B.
I think you are talking about the load obtained by the externally applied uniformly varying load? If yes. The following discussions may clear your doubts. The value of 576 will be obtained if we had a uniformly distributed load UDL (12*48=576) but in this case, we have a uniformly varying load (UVL), hence (1/2*12*48=288). It is the same like the area of a rectangle (UDL) is b*h but the area of a triangle (UVL) is 1/2*b*h.
How did you get 48 lbs/ft from the 60 lbs/ft. The 4 times 12 does not explain enough. What equation did you use to get 48.
Consider two similar triangles (same base to altitude ratio), one having a base of 15ft and another of 12ft. The altitude of a triangle having a base of 15ft is 60, and another of 12ft is unknown (let's say x). So, using ratio 12/x=15/60. Solving this will give x = 48.
How do you determine the distance on where to put the 288 lbs? Do you just divide the total distance by 3?
Whenever we have a triangular shape load (uniformly varying load) the point of application of load will be L/3 from the bigger side (at the centroid of the triangle).
How to know that 288 lbs will act 4 ft from point B
For uniformly varying load(UVL), the load will act at 1/3 of the total length of UVL from the larger side. 12 x 1/3 = 4 ft, larger side is B, hence 4ft from point B.
Behtreen sir..
Can you please do 1-9
Wouldn't the Mb be negative as you have 1152 lbs ft plus Mb equals 0. that you subtract 1152 at otherside?
He made it negative shortly after writing that in the video. This just means moment is actually counter-clockwise
Plz sir solve more
why its time 4
Bcz moment arm is 4ft from point B
why do you 288? isnt it 576?
I think you are talking about the load obtained by the externally applied uniformly varying load? If yes. The following discussions may clear your doubts. The value of 576 will be obtained if we had a uniformly distributed load UDL (12*48=576) but in this case, we have a uniformly varying load (UVL), hence (1/2*12*48=288). It is the same like the area of a rectangle (UDL) is b*h but the area of a triangle (UVL) is 1/2*b*h.
1-6 plsss
It will be uploaded soon.