Second sound travels about 343 meters in one second in air; light takes 1.3 seconds to reach Earth from the surface of the Moon, a distance of 384,400 kilometers. A second is part of other units, such as frequency measured in hertz (inverse seconds or second), speed (meters per second) and acceleration (meters per second squared). The metric system unit becquerel, a measure of radioactive decay, is measured in inverse seconds. The meter is defined in terms of the speed of light and the second; definitions of the metric base units ampere and candela also depend on the second. Of the
Metre per second squared (1 m/s) from a state of rest, when it achieves the speed of 5 m/s after 5 seconds and 10 m/s after 10 seconds. The average acceleration can be calculated by dividing the speed (m/s) by the time (s), so the average acceleration in the first example would be calculated formula_1. Newton's Second Law states that force equals mass multiplied by acceleration. The unit of force is the newton (N), and mass has the SI unit kilogram (kg). One newton equals one kilogram metre per second squared. Therefore, the unit metre per second squared is equivalent to newton per kilogram,