00:01
In our question we are given that a farmer uses cables and winch -pullers b and e to plumb one side of a small barn.
00:07
If it is known that the sum of the movements about the x -axis of the forces exerted by the cables on the barn at points a and d equal 4 -7 -28 pound feet, we need to determine the magnitude of tension in string d -e and a -b, when the tension and called a -b is given to us as 255 pound.
00:31
Now from the schematic diagram of the forces acting on our system, we can calculate the distance between points a and b as follows.
00:39
Distance will be equivalent to which is equal to 17 feet.
00:59
Now the unit vector from point a to b will be given as position vector for point b minus position vector for point a by distance a .b.
01:11
Here the distance between the points a and b is as given where we substitute the values in get.
01:26
The unit vector from a to b to be equal to 1 by 70 minus 1 i cap, 12 .j cap, 12 k cap, respectively.
01:38
Now in order to determine the force vector which is acting at point a from a to b, we have ab to be equal to t of a .v.
01:49
Substituting respective values we get, giving us the equation form to be as follows.
02:15
Now first we'll determine the z component of the force vector which is acting at point a from a to b.
02:20
This will be given as to be equal to k...