Consider the force F acting on an object of mass m in each diagram. The object moves from west to east (direction shown by the longer arrow). Based on the orientation of the force relative to the displacement, identify whether the work done is positive, negative, or zero.
Case (i):
In this case, the direction of force is to the displacement. Therefore, .
Case (ii):
In this case, the force direction is of displacement. Therefore,
Case (iii):
In this case, the direction of force on the object is of displacement. Therefore, .