Quick moments Q

Find the total anticlockwise moment about the origin of a force of 6𝐢+4𝐣
which acts at the point 3𝐢+2𝐣


not sure why i cant do this but any help appreciated!

Any ideas, how do you normally calculate moments, can you use the vector notation ....?

its perp length x force and anticlockwise positive. i tried multiplying them and working out magnitude and working out mag of each vector and multiplying. I can do all the harder moments questions just not these vector ones

Or equivalently its
|a|.|b|.sin(theta)
where theta is the angle between them. You could draw the vectors in cartesian coordinates and work out the (sin of) the angle between them or do the dot/scalar product to get cos(theta) which gives you sin(theta) or do the cross/vector product which gives you the moment directly.

However, a bit of insight (sketch it) should help.

ive tried drawing it but i really dislike vectors, maybe im being stupid but do they not both just point in the topic right quadrant so not 90'? if so what then?