Assign-06-H8152.tex 19/7/2006 17: 3 Page 248
248 GRAPHS AND VECTOR GEOMETRY- Determine the work done by a force ofFnewtons
acting at a pointAon a body, whenAis displaced
to pointB, the co-ordinates ofAandBbeing
(2, 5,−3) and (1,−3, 0) metres respectively, and
whenF= 2 i− 5 j+ 4 knewtons. (4)
12. A force ofF= 3 i− 4 j+knewtons acts on a line
passing through a pointP. Determine moment
Mand its magnitude of the forceFabout a point
QwhenPhas co-ordinates (4,−1, 5) metres and
Qhas co-ordinates (4, 0,−3) metres. (6)