No. A vertical line on a position-time graph would mean that an object moved a given distance in zero time, in other word that it traveled infinitely fast.
Yes virtual object is possible
No, it is not possible for an object's mass to be zero.
No, but the centre of gravity need not be inside the object. Not unless Gravity is not a variable. But it is not possible for an object to not have a center of mass.
Yes, it is possible for the final velocity of an object to be negative. This means that the object is moving in the opposite direction of its initial motion.
No. A vertical line on a speed/time graph would indicate that the object's speed changed from one value to another in zero time. Another way to describe it would be to say that it had infinite acceleration. Neither description is physically possible.
[object Object]
no
Yes, it is possible for the total work done on an object to be negative. This occurs when the force applied to the object is in the opposite direction of its displacement.
The object is actually lighter on the Sun
An object of a contract that is permitted by law and possible of performance
That's equivalent to asking "Can an object move?" - Yes, it can.
More then possible! It is so by definition. Mass is the "amount" of material in an object; weight is the force the object exerts under the influence of gravity.