At t=0, the particle is initially traveling in the negative direction
Work Step by Step
This is a velocity vs. time graph. That means that it graphs the change in velocity as time progresses. The further the line strays from the x-axis, the faster the velocity is. That being said, the velocity can also be negative. If the line is under the x-axis, the velocity can still be fast, it just means that the particle is moving in the negative direction. At t=0, the line is under the x-axis, meaning that the particle is in fact traveling in the negative direction.