00:01
Hello student, here we have the force vector diagram.
00:03
First let us calculate this angle theta dash.
00:06
Using alternate angle theorem, this angle is also theta dash.
00:10
Now in this triangle using trigonometric property, we can write tan theta dash as equal to opposite side by adjacent side that is 3 by 4.
00:21
So we get theta dash as equal to 36 .87 degrees.
00:26
Now let's split the forces into its x and y components.
00:30
The x component of f2 is 5 .2 sine 70 degree.
00:36
The y component of f2 is 5 .2 cos 70 degree.
00:43
The y component of 5 kn force is 5 sine 30 degree.
00:52
The x component of this force is 5 cos 30 degree.
00:58
The x component of the 7 kn force is 7 cos 36 .87 degree.
01:08
Its y component is 7 sine 36 .87 degree.
01:17
The y component of f1 is f1 sine theta and the x component of f1 is f1 cos theta.
01:28
Now for the equilibrium of the point o, the x component of the forces that is sigma fx should add up to 0.
01:39
So we can write 5 .2 sine 70 degree minus 5 cos 30 degree.
01:48
The negative sign is because it acts in the negative x direction...