The position f(t) of a particle moving along a number line is shown.

Question

Link to graph: https://drive.google.com/file/d/11xC8s30vjyekwuxjQol84l3Q-2bmHtfL/view?usp=sharing

A) When is the particle moving forward?

B) When is the particle moving backward?

C) When does the particle turn around?

D) When is the velocity zero for only an instant?

Answer 1

The particle is moving forward if the position increases. That happens from t=-6 to t=-4 and from t=0 to t=2

The particle is moving backwards when the position decreases. That happens from t=-4 to t=0 and from t=2 to t=6

The particle turns around at the point in time when it switches direction. That happens at t=-4, t=0 and t=2.

The instantaneous velocity of the particle is the slope of the position vs time graph. The slope is zero at t=4. That is where it is instantaneously at rest.