00:01
Hello, in this example, we have two people pulling on a new, the forces f1 and f2.
00:19
The angle that the forces make to the horizontal is given.
00:29
The angle here is given as 75 and the angle here is given as 30.
00:40
We are to find a single force that can replace these two forces.
00:44
So we are looking for the resultant of the two forces.
00:48
To do that we resolve them to get their horizontal components and their vertical components.
00:55
If you consider this triangle, this side is the adjacent, so this side is a course.
01:00
So the component here is f2, course, similarly considering this triangle, the horizontal side is adjacent to the angle, so that is f1 cross 75.
01:17
We similarly resolve for the vertical components.
01:21
This side is opposite the angle so this is going to be f1 sign 75 and likewise this side is f2 sign 30 so we first have to find the result of all the vertical forces so resultant in the vertical direction is an f1 sign 75 which is 80 sign 75 plus has f2 70 f2 is 120 120 so 30 that gives us 1 3 7 1 3 7 0 0 0 0 0000 newtons we then find a result out of all the horizontal forces in the x -direction they are opposing so if we choose this as positive x direction then this force is negative so that's going to be f2 cost 30 plus negative of f1 plus 75 that is 80 cross 30 minus 120 so 80 cost 75 sorry i read this one first i wrote this side first so 80 costs 30 that's good and 120 cost 75 okay so that's good.
03:22
Yeah, well this is positive minus that.
03:39
And that gives us 38 .2 mutants.
03:45
So we now find the resultant of these two resultants...