Scalar quantities have magnitude but no direction

Steps:

• Recall that scalars are physical quantities described solely by magnitude, while vectors require both magnitude and direction.
• Examine each option: acceleration involves change in velocity (direction matters), force causes acceleration (directional), mass is just amount of matter, velocity is speed with direction.
• Identify mass as the only one without directional component.
• Confirm using physics definitions: scalars like mass appear in formulas without vector notation (e.g., F = ma, where m is scalar).

Why C is correct:

• Mass is a scalar quantity defined as the measure of matter in an object, with only magnitude and no direction, as per Newton's second law (F = ma).

Why the others are wrong:

• A: Acceleration is a vector, as it has both magnitude and direction (e.g., speeding up forward vs. backward).
• B: Force is a vector, requiring magnitude and direction to specify its effect (e.g., push north vs. south).
• D: Velocity is a vector, combining speed (magnitude) with direction, unlike scalar speed.

Final answer: C