per second squared — from formula anatomyPer second squared (s⁻²) is the unit of acceleration in the International System of Units (SI). It describes how quickly velocity changes per unit time: an acceleration of 1 meter per second squared means that every second, the speed increases by 1 meter per second. This unit appears in Newton's second law (F = ma), where force is mass times acceleration, and in kinematic equations that describe motion under constant acceleration, such as free fall near Earth's surface (approximately 9.8 m/s²).
The concept of acceleration was formalized by Isaac Newton in the 17th century, but the specific unit 'per second squared' became standard with the adoption of the SI system in 1960.
Acceleration is the rate of change of velocity, and velocity is the rate of change of position. So acceleration is a second derivative of position with respect to time, which is why the unit has time squared in the denominator. In practice, you measure a change in speed (meters per second) over a time interval (seconds), and dividing the two gives meters per second squared.
Used in engineering to specify vehicle performance, in physics to calculate forces, and in aerospace to design trajectories and g-force limits.
On the Moon, gravitational acceleration is about 1.6 m/s², so objects fall roughly six times slower than on Earth.
No articles yet