00:01
Okay, so we could use a method of joints to find all of the forces.
00:06
So at joint a, we can draw this diagram where we have f -a -e going in this direction.
00:13
We have f -a -b cosine of theta, and this is f -a -b -sign theta.
00:19
So at joint a, theta, is inverse tangent of 2 over 1 .5, which gives us 53 .15 degrees.
00:27
The sum of all forces in the y direction is equal to 0.
00:31
F -a -b is 6 over -sign of theta, which gives us 7 .5 kiloons.
00:38
And the sum of all the forces in the x direction is equal to 0.
00:42
So f -a -e is f -a -b -cosign of theta, which is 4 .5 kilonutons...