Thread: Vector Geometry

A force F of 4 newtons acts through the point P(5,2,0) in the direction of a = 3i + j + 6k.
Find the moment of the force about the point A(-2, 0, 1). Dimension are in meters.

I'm stuck at start up to do this question.

From definition the moment of the force is
M = r x F - the cross product of two vectors.

OP(5,2,0),
OA(-2, 0, 1),
a ( 3 , 1 , 6 ),
| F | = 4 N.

r = OP - OA.
F = | F | a / |a| .