Answer:
B. 30 m down
Explanation:
In physics we have two types of quantities:
- Scalar quantity: it is a quantity which only has a magnitude (e.g: mass and time are scalar quantities, since they only have a magnitude)
- Vector quantity: it is a quantity which has both a magnitude and a direction (e.g: velocity is a vector quantity, since it has a magnitude (the speed) and a direction)
In this problem, we have:
A. 100 ounces of water --> scalar (this is a volume, which has only a magnitude)
B. 30 m down --> vector (this is a displacement, which has both a magnitude (30 m) and a direction (down)
C. 88 mi/s --> scalar (this is a speed, which has only a magnitude)
D. 45 gallons in a bucket --> scalar (this is a volume, which has only a magnitude)
So, the correct option is B.