Which of the following are vector quantities?

• tension in a cable
• weight of a rock
• volume of a barrel
• temperature of water in a pool
• drift of an ocean current

Is there a place on the Earth where you can walk due South, then due East, and finally due North, and end up at the spot where you started?

Is it possible for the magnitude of the vector difference of two vectors to exceed the magnitude of the vector sum?

Reversing the algebraic sign on the velocity vector reverses the direction of motion.
Is the same statement true for the acceleration vector?