At the moment, I can't find a similar example in my textbook or in my class notes, and I have looked for one and contemplated this problem for the past hour or so. Can anyone give me an idea of what to do to solve this problem?
A constant force F = -3i -2j -1k acts upon an object moving along a straight line from point (-8,0,-10) to point (-9,9,9). Find the work done if the distance is measured in meters and the magnitude of the force is measured in newtons.
Best Answer
The work is defined to be $W = \vec{F} \cdot \vec{d}$ (look here: http://en.wikipedia.org/wiki/Work_(physics) )
I assume in your lecture notes the unit vectors $\vec{e}_1 = (1, 0, 0), \vec{e}_2 = (0, 1, 0), \vec{e}_3 = (0, 0, 1)$ are denored $i,j,k$.
Then $\vec{F} = (-3, -2, -1)$ and $\vec{d} = (-9,9,9)-(-8,0,-10)$. Now all you have to do to finish this homework question is to compute the scalar product $\vec{F} \cdot \vec{d}$.
Let me know if you can do this question now or if you need more help.
By the way: if you are satisfied with an answer you should click on the tick to the left of the answer to accept it. If you don't do that, people here will eventually stop answering your questions.