Answer;
-A model
Explanation;
-A mathematical model is an abstract model that uses mathematical language to describe the behavior of a system. A Mathematical Model tries to copy how a real world thing works using equations.
-Usually a mathematical model describes a system by a set of variables and a set of equations that establish relationships between the variables. Variables may be of many types; real or integer numbers, for example.
-The Area A of a circle with radius r is given by the formula A = πr2. In this formula π ≈ 3.1416... is a number which is a constant, and A and r are variables or unknowns. A is called the subject of the formula.
The answer of this question is D. All of the above
Acceleration happen when an obeject change its velocity. It has nothing to do with speed.
The huge misconception about acceleration is when we thought it only aply if we increase our speed ( in a sport match, sportcaster often describe acceleration as an increase in players speed)
slower, faster, right , left, it does not matter, as long as that object change its velocity, it accelerates
I think it is this because compression stroke it needs to be compressed then open up when started.