2.3 Time, Velocity, and Speed

• the most fundamental physical quantities are defined by how they are measured
• Every measurement of time involves measuring a change in some physical quantity
• It is impossible to know if time passed unless something changes
• Time SI Unit is seconds
• Elapsed Time = final time - initial time
• large displacement in a small amount of time means you have

  large velocity
• Average Velocity = Change in position / Change in time
• Average velocity of an object does not tell us about what happens between the starting and ending point
• Smaller the time intervals are in motion, the more detailed the information
• Average Speed - distance traveled / elapsed time
• Average speed can be greater than average velocity
• average speed is not magnitude of average velocity