Question

What does the graph of x-t, v-t etc. represents?

Answer 1

When you plot any graph for y= f(x), it means that y is a dependent variable that depends on x, and the graph basically traces each value of y, for the corresponding x. Therefore, x-t graph traces how the position of a body changes with time (assuming it is undergoing 1D motion), and v-t graph traces how the velocity changes with time.