What is the easiest way to calculate the rate of motion of an object that changes speed several times during the time of interest?

1)X(t)=Xo±Vo(t)±*a

2)a(t)=

Explanation:

1)with this formula you can determine the position of the object studied when you have an accelerated, or deaccelerated motion, where Xo its your beginning position, and Vo is your beginning speed, and t is the difference of time between the final time and the initial time. The signs of the equation (+ or -) depends if its displacement its increasing on time, or diminishing, it means : positive speed, and acceleration, and in the oposite case negative speed and acceleration respectively.

2)this formula lets you know the variation of speed at each time (considering its constant), so if you have a constant variation of speed along a determined time, then you can use it.

This formula is used in uniformly accelerated rectilinear motion

see earlier answer