Velocity graphs

Question

Predict a velocity time graph for a more complicated motion. The motion is:

1. walk away from the detector slowly and steadily for about 5s.
2. stand still for 5s.
3. walk toward the detector steadily about twice as fast as before.

describe the graph in words.

Answer 1

You would first need to establish a frame of reference (such as walking away from the detector is negative velocity and walking toward the detector is positive). Your problem probably tells you what the frame of reference is but since you didn't share it, I'll choose to use the frame of reference that I mentioned.

Step 1: Walking away slowly and steadily means a low constant negative velocity for the interval t = 0 to t = 5 sec

Step 2: Stand still means zero velocity for t = 5 to t = 10 s

Step 3: Walk toward the detector steadily twice as fast as before means velocity is constant but twice as high as step 1, but now positive. Since d = vt, if v is twice as fast and the distance is the same, then the time must be half as much so t = 10 to t = 12.5s