Which quantity must be known, along with mass, to calculate acceleration using F = m a?

• A. Mass
• B. Velocity
• C. Force
• D. Time

Answer: (C)

Acceleration comes from how much push or pull is acting on an object and how heavy it is. According to F = m a, the acceleration is the force divided by the mass (a = F/m). So if you know the mass and the force, you can determine how quickly the object's velocity changes. Velocity tells you how fast it’s moving now, but not how its speed changes, so it doesn’t let you compute acceleration with this equation. Time isn’t part of this direct relationship either. A quick example: if a 2 kg object experiences a 4 N force, its acceleration is 4 N ÷ 2 kg = 2 m/s².