Acceleration
Acceleration is the rate of change of velocity with time. It tells how quickly velocity changes in magnitude or direction.
Practice This ConceptMain explanation
Teacher explanation
Acceleration can be positive, negative, or zero depending on how velocity changes. If velocity increases uniformly, acceleration is uniform and positive in the chosen direction. If velocity decreases, acceleration may be negative, often called retardation in school-level problems.
Example
A scooter increasing its velocity from 5 m/s to 15 m/s in 5 s has acceleration (15 - 5)/5 = 2 m/s².
Simple analogy
Acceleration checks change in velocity, not just fast motion.
Common confusion
Students often say acceleration means only speeding up, but change in direction or slowing down also involves acceleration.
Exam tip
Use final velocity minus initial velocity, not initial minus final, unless the sign convention demands it.
Answer writing and exam use
1-mark use
Write the exact meaning of acceleration in one clean line.
2-mark use
Define acceleration and add one example or condition.
3-mark use
Explain acceleration, show the method or example, and mention the common mistake.
Practice this concept with focused MCQs
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