Question

how can an object that is oscillating have a 0 velocity

Answer 1

it does have a velocity, really depends on which direction you are talking about

Answer 2

well i calculated the velocity of on object between 0 and pi, the equation i was given was .5cos(2t) t being time in seconds

Answer 3

does that make sense to you?

Answer 4

Think of a pendulum. As it oscillates from one end to other, it changes direction.

So the sign of velocity changes; so it has to be zero somewhere in between.

To be specific the velocity is zero at the extremes and maximum in the middle