1. Time Interval(Δt)
Time (t) is a concept that describes when an event occurs.
Initial time (ti) is when the event began.
Final time (tf) is when the event finished.

2. Time Interval(Δt)
Time interval is the difference between the final and initial times.
Time interval is calculated by:
Both time and time interval are scalar quantities.

3. Ex: 1. What is the position of the sign relative to the tree?
2. What is the time interval to move from the fire hydrant to the sign?

4. Ex: 1. What is the position of the sign relative to the tree?
The position of the sign is 7 m east of the tree
2. What is the time interval to move from the fire hydrant to the sign?
5s – 2s = 3s

5. Watch for Signs
When using vector quantities, opposite directions are given opposite signs.
North, east, up, and right are called positive (+). South, west, down, and left are called negative (–).
Common sign conventions

6. Watch for Signs
North, east, up, and right are called positive (+). South, west, down, and left are called negative (–).
Common sign conventions

7. Ex 3: What is the person’s displacement between 0 s and 15 s .
Ex 4: What distance did the person walk in this same time interval?