00:01
So in this problem, we have three vectors.
00:03
We have force 1, which is equal to 10 .6 .3.
00:10
We have a second force, f2, which is equal to 0, 4 ,9.
00:14
And then we have some third force, f3.
00:17
We don't know anything about f3, but we do know that the sum of the forces is going to equal 0 ,000, right? so we can think of this as three forces acting on a stationary, object if the object is stationary it's not accelerating so it's the sum of the forces must be zero so we need to find f3 such that the sum of the forces is zero and we can do that just by thinking about how we add vectors normally so f1 plus f2 plus f3 that's going to equal the x components of each of these sum together so 10 plus zero plus f3x right the x component of f3 right same for the y's it's going to be six plus four plus f3 y and in the z it'll be three plus nine plus f3 z and we know that this has to equal the zero vector zero zero so now what we're left with is just easy addition problems to make each of these components add up to zero.
01:39
So each of these components have to add up to zero.
01:42
So in an x component, we have 10 plus 0 plus f3x has to equal 0, right? so easily we see that f3x equals negative 10.
01:55
In our y component, we have that 6 plus 4 plus f3x has to equal 0.
02:03
So again, this is, excuse me, that should be f3, 3y...