Distinguishing vectors (magnitude + direction) from scalars (magnitude only)

Steps:

• Recall vectors include displacement, acceleration, force; scalars include energy, power, speed, work.
• Check option A: displacement (vector) and acceleration (vector)—both vectors.
• Check option B: force (vector) and kinetic energy (scalar)—mixed pair.
• Check option C: power (scalar) and speed (scalar)—both scalars; D: work (scalar) and potential energy (scalar)—both scalars.

Why B is correct:

• Force is a vector (defined by magnitude and direction in Newton's laws, e.g., $\vec{F} = m\vec{a}$); kinetic energy is scalar (formula has only magnitude).

Why the others are wrong:

• A: Both displacement and acceleration are vectors (direction-dependent).
• C: Both power and speed are scalars (no direction).
• D: Both work and potential energy are scalars (energy forms without direction).

Final answer: B