Describing and Measuring Motion Chapter 9 Section 1

Are You In Motion?

Describing Motion An object is in motion if its distance from another object is changing.

Reference Points A reference point is a place or object used for comparison to determine if something is in motion. An object is in motion if it changes position relative to a reference point. Stationary objects make good reference points

Relative Motion “You Must Choose wisely”

Measuring Distance International System of Units Scientists use SI units to describe the distance an object moves. When you measure distance, you measure length. The SI unit of length is the meter

Meter Units 1 kilometer (km) = 1000 meters 1 hectometer (hm) = 100 meters 1 decameter (dam) = 10 meters 1 meter (m) = 1 meter 1 decimeter (dm) = .1 meter (10 dm = 1 m) 1 centimeter (cm) = .01 meter (100 cm = 1 m) 1 millimeter (mm) = .001 meter (1,000 mm = 1 m)