00:01
So let's start by understanding the geometry.
00:02
So each diagonal link is 36 inches.
00:05
And given the angle of 30 degrees, the vertical and horizontal component of the link, we have the vertical component is equal to 36 sine 30 degrees, which is equal to 18 inches.
00:21
And then the horizontal is equal to 36 cosine 30 degrees, which is equal to 31 .18 inches.
00:30
This gives us the vertical height and base width of the scissor linkage.
00:35
Now the force analysis on a single link.
00:37
Each diagonal link is a two -force member.
00:39
We'll break the problem into free body diagrams for the entire system and each of the diagonal links.
00:44
So the equilibrium of the entire system, we have the sum of fy, the vertical equilibrium, is equal to zero, which gives us r vertical minus w, which is just zero, which r -vert, vertical.
01:02
Is equal to 1 ,000 pounds.
01:05
And we're going to do the same thing for f of x is equal to zero, which gives us f in.
01:10
And that is equal to the horizontal reactions from link forces...