Which statement correctly pairs a unit with what it measures?

Which statement correctly pairs a unit with what it measures?

• A. BTU is a unit of heat in the English system.
• B. Calorie is a unit of mass.
• C. Watt is a unit of time.
• D. Foot-pound is a unit of velocity.

Answer: (A)

Understanding units means tying them to the physical quantity they quantify. A BTU is an energy unit used in English engineering systems, and it measures heat energy—the amount of energy transferred as heat. That’s why it’s appropriate to say BTU measures energy (heat). The other statements mix up what the units signify: a calorie is also energy, not mass; a watt is a unit of power (energy per unit time), not time itself; and a foot-pound is a unit of work/energy, not velocity. So the pairing that fits is BTU with energy (heat).

Understanding units means tying them to the physical quantity they quantify. A BTU is an energy unit used in English engineering systems, and it measures heat energy—the amount of energy transferred as heat. That’s why it’s appropriate to say BTU measures energy (heat). The other statements mix up what the units signify: a calorie is also energy, not mass; a watt is a unit of power (energy per unit time), not time itself; and a foot-pound is a unit of work/energy, not velocity. So the pairing that fits is BTU with energy (heat).