Acceleration

Identify u, v, and t. Keep units consistent. Substitute in a = (v - u)/t. Interpret the sign of acceleration according to the chosen direction.

A velocity arrow diagram can show increasing, decreasing, or changing direction of velocity.

Writing +3 m/s² for a slowing car without explaining direction is usually wrong because the velocity has decreased.

Acceleration is the rate of change of velocity with time. It tells how quickly velocity changes in magnitude or direction.

Acceleration is the rate of change of velocity with time. It tells how quickly velocity changes in magnitude or direction. Acceleration, a = (v - u) / t, where u is initial velocity, v is final velocity, and t is time. SI unit is m/s². A scooter increasing its velocity from 5 m/s to 15 m/s in 5 s has acceleration (15 - 5)/5 = 2 m/s².

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. Acceleration, a = (v - u) / t, where u is initial velocity, v is final velocity, and t is time. SI unit is m/s². A car slows from 20 m/s to 8 m/s in 4 s. a = (8 - 20)/4 = -12/4 = -3 m/s². The negative sign shows velocity is decreasing in the chosen positive direction. Numericals may ask for acceleration, retardation, final velocity, or time using a = (v - u)/t. Writing +3 m/s² for a slowing car without explaining direction is usually wrong because the velocity has decreased.