Question

Draw position -time graphs for two having the zero velocity

Answer 1

For elevator rides:
Ask yourself three questions:
1. Am I starting on the ground floor or a higher floor?
2. Am I moving up or down?
3. Am I speeding up or slowing down?
Am I starting on the ground floor or a higher floor?
If you are starting on the ground floor:
 the vertical intercept on your position graph will be zero.
If you are starting on a higher floor:
 the vertical intercept on your position graph will be positive.
Am I moving up or down?
If you are moving upward:
 your position values will increase (go away from the horizontal axis)
 your velocity values will be positive
If you are moving downward:
 your position values will decrease (go toward the horizontal axis)
 your velocity values will be negative
Am I speeding up or slowing down?
If you are speeding up:
 the slope of your position graph will get steeper
 your velocity graph will go away from the horizontal axis
 your acceleration values will have the same sign as your velocity values
If you are moving downward:
 the slope of your position graph will get less steep
 your velocity graph will go toward the horizontal axis
 your acceleration values will have the opposite sign of your velocity values