Statics question -civil engineering?

Question

replace the loading on the beams with and equivalent resultant force and specify thier location along each beam measured from the left hand end A. At point A the force is 6kN/m - 6 metres from that point the force is 3kN/m and 4.5 metres from there at point B the force is 5kN/m .

Answer 1

I'm assuming from your description that the loading is composed of two triangular distributed loads. There will be three equivalent loads

Load #1 is the equivalent load for the rectangular portion of the distributed load all along the beam. This is a rectangle 3 kN/m high and 10.5 meters long. The equivalent load is 31.5 kN, and is acting at thru the centroid of the rectangle (which is the middle) at 5.25 m from pt. A.

Load #2 is the equivalent load from the left triangle:
base = 6 m
height = 6-3 = 3 kN/m
equivalent load = 1/2*b*h = 9 kN
The location is through the centroid of the triangle, which is:
1/3*b = 2 m from pt. A

Load #3 is from the right triangle. Similar to above, it is
1/2*4.5*(5-3) = 4.5 kN
Location is 4.5 + 2/3*(6-4.5) = 5.5 m from point A (5 m from point B)

By the way, kN/m is not a moment, as indicated by another responder. kN*m is a moment. kN/m is a distributed load.

Answer 2

You just have to find the resultant vector, if they are both heading in the same direction then you make a parallelogram with them and use pythagorean theorem to find the resultant vector between them. kN/m by the way is what engineers call a moment, not a force - just so you don't get it confused. kN would be a force. kN/m tells you that there is a force being applied over some distance x. The further away the distance, the larger the moment that is being applied. The answer I believe should be 7.8 kN/m.I hope this helps.

Answer 3

Violin is correct. You should state your question a little clearer though so no assumptions need to be made.