This is the manipulated variable in an experiment or study whose presence or degree determines the change in the dependent variable. when graphed this is graphed usually on the horizontal axis.

This is called the independent variable.

Step-by-step explanation:

We know this because it is independent of all outside factors. Additionally, the horizontal axis (also known as the x axis), is the axis known for the independent variable.

b

step-by-step explanation:

a. 12.5 kg

step-by-step explanation:

f = ma

so

m = f/a = (2500 n)/(200 m/s²) = 12.5 kg

1 n = 1 kg·m/s²