Most of physics, and all of science, is concerned with motions. Chapter 11 Motion Most of physics, and all of science, is concerned with motions.

Key Concepts What is needed to describe motion completely? How are distance and displacement different? How do you add displacement?

You must also tell its _______________ at a certain time. To describe motion, you must state the ______________ the object is moving as well as how _______________ the object is moving. You must also tell its _______________ at a certain time. direction fast location

Choosing a Frame of Reference To describe motion accurately and completely, a _____________ of _________________ is necessary. frame reference A frame of reference is a system of objects that are ________ moving with respect to one another. not

Choosing a Frame of Reference How Fast Are You Moving? _________________ motion is movement in relation to a frame of reference. Relative For example, as a train moves past a platform, people standing on the platform will see those on the train _______________ by. speeding

Choosing a Frame of Reference But to someone ______________ ____ a speeding train, others on the train don’t seem to be moving. sitting on

Choosing a Frame of Reference Which Frame Should You Choose? Choosing a ___________________ frame of reference allows you to describe motion in a clear and relevant manner. When you sit on a train and look out a window, a ________________ may help you see how fast you are moving relative to the ______________ If you get up and walk toward the rear of the train, looking at a ______________ shows how fast you are walking relative to the ______________. meaningful treetop ground seat train

Distance is the ___________ of the _________ between two points. Measuring Distance Distance is the ___________ of the _________ between two points. Displacement is the ________________ from the starting point and the length of a ___________ line from the starting point to the ending point. length path direction straight

The SI unit for measuring distance is the _______________ For very large distances, it is more common to make measurements in __________________. Distances that are smaller than a meter are measured in ___________________. meter (m) kilometers (km) centimeters (cm)

Think of a roller coaster track…the distance traveled is the ________ of the roller coaster path

Measuring Displacements Displacement is the direction from the ___________ point to the ________ and the length of the ___________ line between them. After completing a trip around the track, the car’s displacement is _______. starting end straight zero

Combining Displacements Adding displacements uses _____________ addition. vector A vector is a quantity that has ____________ and _________________. magnitude can be _______, ____________, or ______________ vectors are represented on a map with _________ magnitude direction size length amount arrows

Displacement Along a Straight Line Add the magnitudes of two displacement vectors that have the ___________ direction. Two displacement vectors with opposite directions are ______________ from each other. same subtracted

Displacement That Isn’t Along a Straight Path The total distance traveled in the map is shown by the yellow vector lines…the distance adds up to ______ blocks N S 7 W E

Displacement That Isn’t Along a Straight Path Measuring the _______________ _______________ , represented by the red arrow, shows that the displacement is two blocks less than the distance he actually traveled. Displacement = resultant vector N S 5 blocks NE W E

Assessment Questions A car is driving down the highway. From which frame of reference does it appear to not be moving? standing at the side of the road a car driving at the same speed but going the opposite direction sitting inside the car A helicopter flying overhead

Assessment Questions The SI unit of distance that would be most appropriate for measuring a larger distance between two cities is the meter. centimeter. kilometer. mile.

If you walk across town, taking many turns, your displacement is the Assessment Questions If you walk across town, taking many turns, your displacement is the total distance that you traveled. distance and direction of a straight line from your starting point to your ending point. distance in a straight line from your starting point to your ending point. direction from your starting point to your ending point.

Assessment Questions You travel 30 km west of your home and then turn around and start going back home. After traveling 10 km east, what is your displacement from your home? 20 km 20 km west 40 km 40 km west