Am I right? W=Fd, now if that is true then whenever force is negative, then the displacement is negative too.
2007-02-21 15:57:13 · 4 answers · asked by Theta40 7 in Science & Mathematics ➔ Physics
Work is defined as the dot product of a force and a displacement. The dot product is scalar. Therefore it does not have direction, hence no sign. It is an absolute value.
2007-02-21 16:14:23 · answer #1 · answered by Anonymous · 2⤊ 1⤋
This is an interesting question, because it does need a careful reply. While it's true that the force vector has a direction, which can be "negative", the displacement must ALSO be measured in the direction of the force. Hence, if the force vector is positive, so is the displacement, and work is positive. If the force vector is negative, so is the displacement, and the work is positive.
If you "ran the video backwards", so that while the force vector is in one direction, the displacement goes opposite in the direction of the force, then, yes! Work is negative! That should make sense, because in running the video backwards, you are putting the work energy back into the source of energy behind the force.
2007-02-21 16:05:01 · answer #2 · answered by Scythian1950 7 · 1⤊ 1⤋
Not necessarily. If the negative force isn't enough to overcome a positive force acting on the object (or something like friction, which would hold the object in place), displacement wouldn't be negative. In that case, however, the negative force would be doing no work.
So if the net force is negative, it's more accurate to say the displacement has to be non-positive, as it could be zero.
2007-02-21 16:06:48 · answer #3 · answered by The Ry-Guy 5 · 0⤊ 1⤋
no displacement cant b negative and also work is always positive
2007-02-21 16:04:32 · answer #4 · answered by rohan1985 2 · 1⤊ 1⤋