2 Motion depends on frame of reference. A frame of reference upon the background used to observe Motion suppose you are riding a moving walkway such as the ones you might see at many airports. What is your frame of reference? Are you moving?
3 If your friend is riding with you you are not moving compared to him or her. Tour friend is a Frame of reference. your distance from your friend does not change so there is no motion relative to your friend. However compared to someone who is not on the walkway you are moving. Your distance from that person constantly changes.
4 Scientists try not to say that something is in motion without stating the frame of reference. Relative motion is the motion of an object compared
To a frame of reference. A person on moving walkway has on relative motion compared to someone who is also on the walkway. That some person does have relation or something off the walkway.
5 Because motion involves changing distance you must be able to measure distance to measure motion. Distance is the length or space between two objects or places. When discussing motion distance often refers to how far an objects moves from its starting point. A distance measurement is a measurement of length. Distance can be measurement using a tool that is used to measure length. Distance is measured using units of length such as meters miles or kilometers.
6Suppose you are traveling from one town to another. If you travel on a straight road the distance might be 45 km. Another road between the towns might in volve several turns. The distance between the towns along that path might be 62 km. Although you start and stop at the same places distance might be different for each path.
7 Sometimes you might want to know the shortest straight-line distance from one place to another. You might not be able to follow this path because there are things in your way. However you can measure the straight-line distance. It well be the same measurement no matter how many different paths there might be. The measurement well tell you how far one place or object is from another place or object.
8 To describe where one object is relative to another object you need more than a distance measurement. You also need to know the direction one object is from the other. Displacement is the distance and direction of an object in position from a starting point.
9 The distance you travel between two object is not necessarily the length of the displacement. Suppose your school is three blocks north and three blocks east from your home. The distance between home and school depends on the path you take. You might walk three blocks north and three blocks east for a distance of six blocks. Or you might go out of your way to go to a friend s home. This might take you one block north one block west two blocks north and four blocks east. The distance for this path is eight blocks.
10 The displacement is the shortest distance between your home and school plus the direction you need to travel to get from place to place. The displacement is just over four blocks northeast. You might not be able to follow that exact path if buildings or other things block your way. But whatever path you take the displacement from your home to your school is the same.