Describing & Measuring Motion

An object is in (a)   if its distance from another object is changing.

A _________ _____ is a place or object used for comparison to determine if something is in motion.

(a)  

An object is in motion if it changes position relative to a reference point.

• True

• False

Objects that we can call (a)   such as a tree, a sign, or a building, make good references points.

Why do scientists use the same system of measurement?

The system of measurement is called the _____________ ______ __ _____.

(a)  

Scientists use SI units to describe the distance an object moves.

• True

• False

When you measure distance, you measure length. The SI unit of length is the (a)   (m).

The length of an object smaller than a meter often is measured in a unit called the (a)   (cm).

A centimeter is one hundredth of a meter, so there are centimeters in a meter.

• 100

• 10

• 1000

• 10000