An object moves along a line in such a way that is position at time t is given by a. Find the velocity v(t) and acceleration a(t) of the object.
b. When is the object stationary? When is it advancing? Retreating?

I need to know how to do letter b.

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?