Ch+2+Sec+2+KirnumB

Section 2
toc What do you see? I see how the person takes fewer steps with an increased speed and takes more steps with a slower speed.

What Do you think 100 mi/h is the speed that the ball is traveling, this gives you a larger amount of time with a larger amount of speed. 45 m/s is a smaller time with a smaller speed. They are both proportions of the same thing.

Physics Talk
 * Constant Speed and Acceleration Using a Ticker Timer
 * Ticker TImer:
 * You use the lengths of paper tame that passed through it during equal time intervals to find the sped of the tape and its acceleration
 * Constant Speed: Equal distance between dots
 * The slower you travel, the shorter distance between dots
 * [[image:Picture_9.png width="489" height="161"]]
 * You can also tell if the person was accelerating
 * if they were, the distances between the dots weren't equal
 * Positive acceleration- distances get larger
 * Negative: Distances get shorter
 * [[image:Picture_10.png width="336" height="180"]]
 * Calculating Speed
 * Speed is a ratio of distance traveled to time taken
 * Average speed= (distance traveled)/(time elapsed)
 * Calculating Acceleration
 * when an object changes speed it accelerates
 * acceleration= (change in speed)/(time interval)
 * Average Velocity
 * how fast position changes
 * Large distances or times over which there may be variations
 * variations: it is an AVERAGE they aren't all equal
 * v=∆d/∆t
 * Acceleration
 * how fast speed changes
 * a= ∆v/∆t
 * Positive Acceleration
 * increasing speed
 * Negative Acceleration
 * decreasing speed
 * When v and A have the same sides increasing speed
 * When v and A have different sides decreasing speed

Checking Up Questions 1.) a. Dots that are the same distance appart b. Dots moving farther and farther apart from eachother c. Dots moving closer and closer to eachother 2.) 8 m/s (work in notebook) 3.) The Difference between instantaneous speed and average speed is that instantaneous speed is speed at an instant, average speed is speed during the entire length of the motion. 4.)27.8 m/s (work in notebook)

Investigate 1.) a. Same distance inbetween dots b. farther apart c. Closer together d. If you increase your speed, the dots will end up being farther appart 4.) a. They tend to decrease b. Since they are more spaced out, the faster the tap was pulled, the longer the paper will be 5.) b. My movement wasn't constant

PTG



What do you think now? 100 mi/h and 45 m/s are measurements of speed, that can be from an average or instantaneous. They show how much of the distance was traveled (100 miles and 45 miles) in an elapsed time (hours and seconds).

Reflecting on the Section and the Challenge
 * I can use this section to provide examples through the challenge.

Physics Plus

(1m/s^2) || golf cart, jogger, || (100 m/s^2) || **rebounding object ||
 * Velocity || acceleration || examples ||
 * small (1m/s) || small
 * small (1m/s) || big
 * big || small || big truck ||
 * big || big || airplane ||
 * rebounding- bouncing off a surface and changing directions
 * you assume that the acceleration is constant during entire process
 * it has 3 stages
 * 1) a ball being dropped (-vi)
 * 2) hits the ground
 * 3) bounces up (vf)