Scalar vs. Vector Products in Physics

Steps:

• Identify scalar (magnitude only) vs. vector (magnitude and direction) quantities.
• Determine product type: scalar × scalar = scalar; scalar × vector = vector; vector · vector = scalar.
• Evaluate each option for resulting quantity type.
• Select option yielding scalar via directional component.

Why A is correct:

• Represents work = force · displacement (dot product), a scalar by definition in mechanics.

Why the others are wrong:

• B: Mass (scalar) × acceleration (vector) = force (vector).
• C: Pressure (scalar) × area (scalar) = force magnitude, but direction normal to surface makes it vector.
• D: Velocity (vector) × time (scalar) = displacement (vector).

Final answer: A