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Chapter 11 Motion Sec. 11.1 Frame of reference A system of objects that are not moving with respect to one another Used in order to see motion Describes motion accurately Relative Motion Movement in relation to a frame of reference Ex. People in a car appear to be moving to the people on the side of the road But when people in the car look at one another they do not seem to be moving at all. Interactive practice with frame of reference http://www.amnh.org/learn/pd/physical_science/week2/frame_referen ce.html http://www.physics-chemistry-interactive-flashanimation.com/mechanics_forces_gravitation_energy_ interactive/frame_of_reference_motion_child_ball_trai n.htm Video on frame of reference OLD SCHOOL http://archive.org/details/frames_of _reference Distance Length of a path between 2 points The SI unit for distance is the meter Vs. Displacement Length of straight line from start to end Vector Quantity that has magnitude (size, length or amount) and direction Arrows represent vectors (they show a numerical value and a direction) Resultant Vector Vector sum of 2 or more vectors Points directly from the starting point to the ending point Go over this with the class before the activity Distance vs displacement http://physics.info/displacement/ Quick Lab Turn to page 330 Obtain a sheet of graph paper and a ruler Follow the direction for the quick lab Turn your lab in 1paper with two names on it. Sec 11.2 speed Ratio of the distance an object moves to the amount of time the object moves Write formula page 333 Average speed- entire trip Instantaneous speed- measured at a particular instant (Ex. Speedometer) Average Speed Average Speed = Total Distance Total Time V`= d t http://www.nbclearn.com/nfl/cuecard/5 0770 Average Speed Total distance/total time Ex. Drove 50 m in 28 sec, drove 200 m in 180 sec, stopped for 50 sec, drove 100 m in 100 sec. What is average speed? 50 m +200m +0 m + 100 m=350m 28 s + 180 s + 50 s + 100 s=358s = 350 m /358 s = _0.98__ m/s More practice Let’s work through math skills/practice page 333 together Copy steps into your notes from page 333 Practice #1 Answer 0.1 km/min Practice #2 Answer 62 km/hr More v=d/t Icurio activity http://www.icurio.com/goExternal?np =/templates/sections/external/extern al.ftl&pp=/templates/sections/frame work/error.ftl&evlCode=272477&prod uctName=icurio&al=High Graphing Motion Distance-Time graph The slope of the line on the graph is the Slope=rise run Book page 334 Let’s read through this and look at the bottom of the page A steeper slope on a distance time graph indicates a higher . You tube Moving man http://www.youtube.com/watch?v=x 2ve5yucNPQ Click the link below to do the interactive http://zonalandeducation.com/mstm/ physics/mechanics/kinematics/xvaVs Time/xVsTime.html Click this link next and do this interactive second http://www.mangahigh.com/en/math s_games/shape/speed_distance_time /distancetime_graphs Practice with graphs http://www.thatquiz.org/tq/previewt est?C/F/D/L/34921292529116 How does a speedometer work? It measures distance (the number of times the tires turn) and speed ( their rate of turning) Velocity Description of both speed and direction of motion Velocity is a vector A change in speed, direction, or both will result in a change of velocity Discovery ed interactive http://app.discoveryeducation.com/ http://www.physicsclassroom.com/cl ass/vectors/u3l1b.cfm Sec.11.3 Acceleration The rate at which velocity changes Changes speed, direction, or both Acceleration=change in velocity total time a= (vf-vi) t Extra Help To rearrange the equation to solve for other variables, especially vi or vf 1.multiply both side of the equation by t 2.cancel the t/t on the right side of the equation 3.add vi to both sides of the equation Practice this 1. a sprinter accelerates from the starting block to a speed of 8.0 m/s in 4.0 s. What is the magnitude of the sprinters acceleration? (2.0 m/s2) 2. a car is traveling at 14 m/s. Stepping on the gas pedal causes the car to accelerate at 2.0 m/s2. How long does the driver have to step on the pedal to reach a speed of 18 m/s? (2.0 s) Free fall http://www.regentsprep.org/Regents/physics/phys01/accgravi/index.htm Click and go through the link with the class. Acceleration due to change in The movement of an object toward Earth solely because of gravity Constant Acceleration A steady change in velocity Changes the same amount each second Instantaneous Acceleration How fast a velocity is changing at a specific instant Graphs of Accelerated Motion Speed-time graph The slope of the line on the graph is the acceleration Constant acceleration is demonstrated with a straight line or linear graph Accelerated motion is demonstrated with a curved line or nonlinear graph ex. A car at a stop light accelerates (when green) to 15m/s in 5 sec. What was their acceleration? Final = 15 m/s Initial = 0 m/s Time = 5 sec a= 15 – 0/5 = 3 m/s2 Ex. A car traveling 30 m/s comes to a stop in 3 sec. What was their acceleration? Final Initial = 0 m/s = 30 m/s Time = 3 sec a = 0 –30/3 -10m/s2 negative slowing down Let’s practice Page 346 Math skills copy the example Math Practice #1 answer -0.5 m/s2 #2 answer 36 m/s #3 answer 19.6m/s #4 answer -25 m/s Compare speed and velocity http://www.youtube.com/watch?v=D Rb5PSxJerM Wrap up and review of Speed, Velocity and Acceleration Song http://www.youtube.com/watch?v=rZ o8-ihCA9E