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Kinematics = study of motion. How many dimensions do we live in?. 4. How do you know something is moving?. Need frame of reference – backdrop. One -Dimensional (1-d) Motion Simplest type. What is motion? Define it!. 2. Are you in motion right now? Explain.
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Kinematics = study of motion How many dimensions do we live in? 4.
How do you know something is moving? • Need frame of reference – backdrop.
One -Dimensional (1-d) Motion Simplest type. • What is motion? Define it! 2. Are you in motion right now? Explain.
Motion = change position, Dx, along x, y, z relative to reference frame. • Distance (d) = total path length, how much ground covered – no direction. A scalar quantity! • 10 m East the same as 10 m west • Displacement (s) well (d) – is distance & direction from start point. It is Dx, Dy Dz. VECTOR Quantity. • Some directions pos +, some neg -.
Distance & Displacement • Move from position 2m to 10 meters. • What distance was covered? • 8 m • DisplacementDx = xf – xi. • 10 m – 2 m. • = +8m.
Distance & Displacement • Move from 20 to 5 meters, • What distance was covered? • 15 m • Dx = xf – xi. 5 m – 20 m = _____. • Displacement = - 15m.
Direction of D position is positive or negative (+ or -) • Positive directions: • Right, up, east, north • Negative directions: • Down, left, west, south
Ex: I jog 2 km south. • What is my distance? • 2 km • What is my displacement? • - 2 km • or • 2 km South
Ex: Walk 6 km N, 4 km S. • What is your distance walked? • 10 km • What is your displacement? • 2 km N.
Vectors Graphically Represented with scaled arrows. • If end displacement of bee is 10 km southeast, sketch a scaled arrow pointing that way. • At 1 cm = 1 km then arrow is a 10 cm sketch pointin SE.
Distance & displacement 5 min. https://www.youtube.com/watch?v=oEWq-JmJut0
Simplest form of motion is 1 dimensional or 1-d. • Straight line motion .
Speed rate you cover a distance – scalar (v) • Velocity – rate you change position including direction. (v)
Average Speed vs. Velocity Speed = total distance/time SCALAR. No direction indicated. speed = d/t Velocity = displacement/time VECTOR. Includes direction. v = Dx/t, v= Ds/t v = d tot /t tot. Vel direction/sign = displacement (Dx)
Isolate each variable. • v = d/t • v*t = d • t = d/v.
Equations are for average not instantaneous velocity. Only if object travels at constant velocity, average = instantaneous.
Read text pg 40 - 42 • Velocity example problem sheet in class. • Do Wksht
In class Problems pg 44 #1, 4, 6. • HwkRead pg 40 – 44. Be prepared to answer question on reading as quiz. • Do wksht and pg 44 #3 - 6
Slope = 0 Slope = neg Neg vel
Acceleration Instantaneous velocity = slope of tangent.