UNIT 1 Motion Graphs LyzinskiPhysics x t Days

Day #7 * a-t graphs * “THE MAP”

x t UNIFORM Velocity Speed increases as slope increases x t Object at REST x t Object Positively Accelerating x t Object Negatively Accelerating x t Moving forward or backward x-t ‘s x t Changing Direction x t Object Speeding up

v t UNIFORM Positive (+) Acceleration Acceleration increases as slope increases v t UNIFORM Velocity (no acceleration) Object at REST v t Changing Direction v-t ‘s v t UNIFORM Negative (-) Acceleration v t

a t UNIFORM Acceleration UNIFORM Velocity OR An Object at REST a-t ‘s a t

Graph Re-Cap Type of graphSlope of a line segment Slope of the tangent to the curve at a point x-t v-t a-t Average velocity Instantaneous Velocity Average acceleration Instantaneous acceleration JERK!!!!!!!!!!! (no jerks on test ) Area under curve x-t v-t a-t Tells you nothing Displacement (  x) Change in velocity (  v)

a-t graphs t (sec) a (m/s 2 ) t 0 t 1 The area under the curve between any two times is the CHANGE in VELOCITY during that time period. Slopes???? No jerks on test

THE MAP!!!! x-t v-ta-t SLOPE AREA “3 towns, 4 roads” xx vv

a = 6 m/s 2 1) 2)  v = area = 4 (6) + (2.5 * -9) = 1.5 m/s Open to in your Unit 1 packet 5

Either at rest or at a constant velocity, const + accel, const – accel, non-constant – accel, non-constant + accel 3) 4)  v = area = 2.5 (6) = 15 m/s   v = v 2 – v 1  v 1 = (-5) – 15 = -20 m/s Open to in your Unit 1 packet 5

Day #8 FREE-FALL LAB

Day #9 Drawing Physics Graphs from word-problem scenarios

Day #10 Given x-t or v-t graphs, draw the corresponding v-t or x-t (or even a-t) graph. v t x t

Take out your Green Handout

Drawing an x-t from a v-t t (hr) v (km/hr) t (hr) x (km) Find the area under the curve in each interval to get the displacement in each interval Use these displacements (making sure to start at x i, which should be given) to find the pts on the d-t curve 4m 24m 40m 18m 3m 0m - 18m -10m “Connect the dots” and then CHECK IT!!!!

Drawing a v-t from an x-t Find the slope of each “Non-curved” interval x (yd) t (min) v (yd/min) t (min) 6 yd/min -4 yd/min 0 yd/min Plot these slopes (which are average velocities) For curved d-t regions, draw a sloped segment on the v-t + accel. region (+ slope) This only works if the accelerations on the x-t graph are assumed to be constant