ch2_chjb

= = =Linear Motion = 
 * Vocabulary **
 * **Relative**- Regarded in relation to something else. Depends on the point of view, or frame of reference.
 * **Rate**- Quantity divided by time.
 * **Speed**- A measure of how fast something is moving.
 * **Instantaneous Speed**- The speed at any instant.
 * **Velocity**- The speed in any given direction.
 * **Acceleration**- The rate at which the velocity is changing.
 * **Free Fall**- Motion under the influence of the gravitational force only.
 * **Elapsed Time**- The time that has elapsed, or passed, since the beginning of the fall.
 * **Average Speed-** Path distance divided by time interval.

=<span style="font-family: Georgia, serif;">Examples = <span style="font-family: Georgia, serif;"> math Average\ Speed=\frac{Total\ Distance\ Covered}{Time\ Interval} math math Average\ Speed=\frac{120\ km}{6\ h} math math Average\ Speed=20\frac{km}{h} math || math Acceleration=\frac{Change in Speed}{Time Interval} math math Acceleration=\frac{10\ km/h}{5\ s} math math Acceleration=2\frac{km}{h*s} math ||
 * <span style="font-family: Georgia, serif;">**Average Speed:** If a cheetah runs a distance of 120 km in 6 hours. What is the cheetah's average speed?
 * **<span style="font-family: Georgia, serif;">Acceleration: **<span style="font-family: Georgia, serif;"> Within a 5 s interval, a car increases its speed from 30 km/h to 40 km/h. What is the car's acceleration?

<span style="color: #9b00ff; font-family: Georgia, serif;"> <span class="Apple-style-span" style="line-height: normal; border-collapse: collapse; webkit-border-horizontal-spacing: 2px; webkit-border-vertical-spacing: 2px;"><span style="color: rgb(170,170,170);"> =<span class="Apple-style-span" style="line-height: normal; border-collapse: collapse; webkit-border-horizontal-spacing: 2px; webkit-border-vertical-spacing: 2px;"><span style="color: #000000; font-family: Georgia, serif;">  2.1 - Motion Is Relative     =
 * Everything moves relative to the sun and the stars
 * Even when something is at rest, it is moving relative to the sun, stars, or galaxy
 * All motion is relative to something else
 * <span style="font-size: 130%; color: #26e839; font-family: Georgia, serif;"> 2.2 - Speed **
 * The speed of an object measures how fast the object is moving
 * Speed is the rate at which something is moving (rate = divided by time)
 * To describe speed, units are combined (mi/h, km/h, etc.)
 * Instantaneous speed describes the speed of an object at any instant
 * Average speed is the total distance covered divided by the time


 * <span style="font-size: 130%; color: #44b9e4; font-family: Georgia, serif;">2.3 - Velocity **
 * Velocity is the speed of an object in any given direction
 * Speed and velocity are very similar, but velocity deals with direction and speed does not
 * Constant velocity requires constant speed and direction
 * If the speed or the direction of an object changes, the velocity changes

<span style="font-size: 130%; color: #e91c82; font-family: Georgia, serif;">**2.4 - Acceleration**
 * The rate at which the velocity changes is acceleration
 * A car accelerates when the driver steps on the gas pedal, which makes the car move faster
 * If something has a good acceleration, it does not mean that it is fast, but that it can change its velocity quickly
 * Acceleration is a change in speed and direction

= =
 * <span style="font-size: 130%; color: #b7ae15; font-family: Georgia, serif;">2.5 - Free Fall: How Fast **
 * If an object is in free fall, there is no air resistance on the object and gravity is the only force acting on it
 * The elapsed time of the fall is the time from the beginning to the end of the fall
 * The acceleration of an object falling freely is about 10 meters per second squared

=**<span style="color: rgb(18,0,255); font-family: Georgia, serif;">2.6 - Free Fall: How Far **= > <span style="color: rgb(0,0,0);"> =**<span style="color: rgb(219,93,15); font-family: Georgia, serif;"> <span style="color: rgb(219,93,15); font-family: Georgia, serif;">2.7 - Graphs of Motion **=
 * <span style="color: rgb(0,0,0); font-family: Georgia, serif;">Speed and distance are not the same.

<span style="font-family: Georgia, serif;"> =**<span style="color: rgb(32,210,25); font-family: Georgia, serif;">2.8 - Air Resistance and Falling Objects **= <span style="color: rgb(170,170,170);">* <span style="color: rgb(0,0,0); font-family: Georgia, serif;">Air resistance less noticeably affects the motion of more compact objects
 * <span style="color: rgb(0,0,0); font-family: Georgia, serif;">You can use graphs to visually describe relationships between velocity and acceleration
 * <span style="color: rgb(0,0,0); font-family: Georgia, serif;">Linearity- When the graph shows a straight line
 * <span style="color: rgb(0,0,0); font-family: Georgia, serif;">Slope- Vertical change divided by the horizontal change for any part of the line
 * <span style="color: rgb(0,0,0); font-family: Georgia, serif;">Parabolic- When we double one variable, the other is quadrupled