You will learn the meaning of an object's position, the difference between distance and displacement and some basic graphing of position vs. time.
When beginning a one dimensional problem, define a positive direction. The other direction is then taken to be negative. Traditionally, "positive" is taken to mean "to the right"; however, any definition of direction used consistently throughout the problem will yield the right answer.
Problem: An indecisive car goes 120 m North, then 30 m south then 60m North. What is the car's distance and displacement?
Distance is the total amount traveled. Thus distance = 120 + 30 + 60 m = 210 m
Displacement is the amount displaced from the starting position. Thus displacement = 120 - 30 + 60 m = 150 m.
Watch this Explanation
Time for Practice
What is the difference between distance
dand displacement △x?
Does the odometer reading in a car measure distance or displacement?
Imagine a fox darting around in the woods for several hours. Can the displacement
△xof the fox from his initial position ever be larger than the total distance dhe traveled? Explain.
Your brother borrowed the scissors from your room and now you want to use them. Do you care about the distance the scissors have traveled or their displacement? Explain your answer.
You’re trying to predict how long it’s going to take to get to Los Angeles for the long weekend. Do you care about the distance you’ll travel or your displacement? Explain your answer.
3. No. Distance takes into account the curves and turns that the fox takes, but displacement is only the distance from where the fox started to where the fox ended.
5. Distance. You need to account for all of the curves of the road so that you can make sure you have enough gas for the trip!