A forceFof 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.

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- Apr 14th 2010, 09:18 AMwkn0524Vector 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. - Apr 14th 2010, 02:42 PMzzzoak
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**| .