Why Is Acceleration Parallel to Net Force Vector?
Understand why acceleration always aligns with the net force per Newton’s second law. Clarify common confusions with velocity and displacement for physics exams.
Question
Acceleration is always in the direction of the ______________.
A. Initial velocity
B. Net force
C. Displacement
D. Final velocity
Answer
B. Net force
Explanation
Newton’s second law of motion states that the acceleration of an object is directly proportional to the net force acting on it and occurs in the same direction as that net force. The net force vector determines both the magnitude and direction of acceleration, regardless of the object’s initial or final velocity, or its displacement path. For instance, if a net force points eastward, the acceleration will also point eastward, causing any velocity change in that direction; options A, C, and D fail because velocity directions vary independently (e.g., initial velocity could oppose acceleration, as in braking).