the first few steps the program let us next look at python program for evaluating this simple formula assume the program is contained as text in file named ball py the text looks as follows (file ball py)program for computing the height of ball in vertical motion initial velocity acceleration of gravity time * * * ** vertical position print computer programs and parts of programs are typeset with blue background in this book slightly darker top and bottom baras aboveindicates that the code is complete program that can be run as it stands without the barsthe code is just snippet and will (normallyneed additional lines to run properly dissection of the program computer program is plain textas here in the file ball pywhich contains instructions to the computer humans can read the code and understand what the program is capable of doingbut the program itself does not trigger any actions on computer before another programthe python interpreterreads the program text and translates this text into specific actions you must learn to play the role of computer although python is responsible for reading and understanding your programit is of fundamental importance that you fully understand the program yourself you have to know the implication of every instruction in the program and be able to figure out the consequences of the instructions in other wordsyou must be able to play the role of computer the reason for this strong demand of knowledge is that errors unavoidablyand quite oftenwill be committed in the program textand to track down these errorsyou have to simulate what the computer does with the program nextwe shall explain all the text in ball py in full detail when you run your program in pythonit will interpret the text in your file line by linefrom the topreading each line from left to right the first line it reads is program for computing the height of ball in vertical motion this line is what we call comment that isthe line is not meant for python to read and executebut rather for human that reads the code and tries to understand what is going on thereforeone rule in python says that whenever python encounters