Answer:

Explanation:
The speed of the ball in meters per second is

Where t denotes the number of seconds since the ball has been thrown and
is the initial speed of the ball. Then:

If the ball travels 25 meters during the first 2 seconds after it is thrown, what was the initial speed of the ball
Also, for constant acceleration motion, the average velocity is equal to the sum of final and initial velocities divided by 2 and to the distance divided by the time:

Where you know:
Substituting (the units are ommited in the equationn, but added at end of the answer):


Thus, you have a system of equations:


Substituting the second into the first:


Answer:
Humans were nomads. Their wandering was mainly in search of food and shelter. When they found that certain places had an abundance of food – plant food or animals for hunting, they stayed on. They observed the plants, their growth and when these food sources diminished, they grew plants themselves, from the seeds they collected. This is how agriculture came about.
When humans stopped their nomadic ways and stayed together, it paved the way for formation of the human social structure. Hierarchies were established in due course.