00:01
We're asked to find the moment from d to b given that the force from a to e is 55 newtons.
00:07
And i went ahead and found these position vectors of the different locations on the given figure.
00:14
So to start with, i'm going to write down the formula that's going to calculate the moment from d to b.
00:22
So the moment from d to b, we're going to have to find the unit vector from d to b.
00:34
And take the dot product of the da vector and take the cross product of the force, the force vector, so to start with, i'm going to first find, i'm going to first find this term, i'm going to first find the unit vector.
00:59
So to find the unit vector db, we need to find the db vector.
01:04
So the db vector, that's going to be equal to the b vector minus the e vector, and that will give us a vector of 1 .2i minus 0 .35j.
01:33
And to calculate the unit vector, the unit vector of dd, we can do the dd vector divided by its magnitude.
01:49
And this will give us a unit vector of 0 .96i minus 0 .28j.
02:19
And next we're going to calculate this term, the da vector.
02:25
So to calculate the da vector, we do a vector minus d vector, and that will give us a vector, that will give us a vector, that will give us a vector of negative 0 .1j, plus 0 .2k.
02:57
And lastly, we're going to calculate the force vector...