Speed indicates how much the position of a moving object changes in space per unit of time. The symbol for speed is v, derived from the Latin word vēlōcitās - speed. The SI unit of speed is meters per second (m/s or m·s-1)
$$v=\frac{s}{t}$$
where,
s— displacement
t— time taken.
The equation of uniformly accelerated linear motion is a mathematical description of an object's motion where the velocity changes at a constant rate with respect to time.
$$v = v_0 + at$$
where,
v0— initial velocity
v— final velocity
a— acceleration
t— time of motion.
This formula is applicable only for uniformly thrown bodies in the vertical direction, assuming air resistance and other factors are negligible.
$$v = v_0 - gt$$
where,
v0— initial velocity
v— final velocity
g— gravitational acceleration on Earth
t— time of motion.
In the case of non-uniform motion, the average speed, which is the ratio of the total displacement to the total time taken, can be calculated:
$$\bar{v}=\frac{\Delta s}{\Delta t}$$
$$c=299\, 792\, 458\, \mathrm{m/s}$$