8th Gr Science Ch 18

When it is changing position

When an object moves from one location to another

• An object changes position if it moves relative to a reference point.
• eg. Starting the 100m dash behind the starting line then your position changes by 100m at race's end

Motion occurs when something changes position relative to a reference point

• Distance = distance traveled
• eg. the length of a route

Displacement = the direction and difference in position between your starting and ending points.

Only if the object moves in a straight line

Speed = the distance an object travels in a unit of time

speed (in meters per second) = distance (in meters)/time (in secs) OR s = d/t

• True
• for example it can be calculated in kilometers per hour

The speed of an object at one instant of time is the object's instantaneous speed

A distance time graph can be used to represent the motion of an object

Distance is plotted on the Y or vertical axis

Time is plotted on the X or horizontal axis of a distance time graph representing the motion of an object?

You can use a distance time graph to compare the speed of objects.