Chapter 11 Motion

Sec 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.

Video on frame of reference OLD SCHOOL _reference _reference ce.html Interactive practice with frame of reference animation.com/mechanics_forces_gravitation_energy_ interactive/frame_of_reference_motion_child_ball_trai n.htm

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

Distance vs displacement Go over this with the class before the activity

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 Total Time V`= d V`= d t

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 m=350m 28 s s + 50 s 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

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Graphing Motion

You tube Moving man 2ve5yucNPQ physics/mechanics/kinematics/xvaVs Time/xVsTime.html Click the link below to do the interactive Click this link next and do this interactive second s_games/shape/speed_distance_time /distancetime_graphs

Practice with graphs est?C/F/D/L/ est?C/F/D/L/

How does a speedometer work? It measures distance (the number of times the tires turn) and speed ( their rate of turning) ( their rate of turning)

Velocity Description of both speed speed and direction direction of motion Velocity is a vector A change in speed, speed, direction, direction, or both will result in a change of velocity

Discovery ed interactive

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Sec.11.3 Acceleration The rate at which velocity changes Changes speed, direction, or both Acceleration=change in velocity total time total time a= (v f -v i ) a= (v f -v i ) t

Extra Help To rearrange the equation to solve for other variables, especially v i or v f 1.multiply both side of the equation by t 2.cancel the t/t on the right side of the equation 3.add v i 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/s 2 ) 2. a car is traveling at 14 m/s. Stepping on the gas pedal causes the car to accelerate at 2.0 m/s 2. m/s 2. How long does the driver have to step on the pedal to reach a speed of 18 m/s? (2.0 s)

Free fall Click and go through the link with the class.

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?

Ex. A car traveling 30 m/s comes to a stop in 3 sec. What was their acceleration?

Let’s practice Page 346 Math skills copy the example Math Practice #1 answer -0.5 m/s 2 #2 answer 36 m/s #3 answer 19.6m/s #4 answer -25 m/s

Compare speed and velocity Rb5PSxJerM Rb5PSxJerM

Wrap up and review of Speed, Velocity and Acceleration Song o8-ihCA9E