2 Displacement Change in position of an object Frame of reference A point against which position is measuredExample: A train traveling between stationsIt is in motion when measured against the track.It is stationary when measured against a seat.
3 Displacement Not equal to distance traveled Scalar vs. Vector Distance vs. Displacement
4 Displacement (x)Straight line distance from the initial position to the final position (change in position)Can be positive or negative
5 Displacement (x) What is the displacement for the objects shown? Answer: 70 cmAnswer: -60 cm
7 Speed vs.Velocity Scalar vs. Vector Distance vs. Displacement
8 Speed Speed does not include direction while velocity does. Speed uses distance rather than displacement.In a round trip, the average velocity is zero but the average speed is not zero.
9 Average Velocity = (ΔX/Δt) = displacement/time interval Displacement in a given timeAverage Velocity = (ΔX/Δt) = displacement/time interval
10 Average VelocityHow would you describe the motion shown by this graph?
11 Average Velocity Describe the motion of each object. Answers Object 1: constant velocity to the right or upwardObject 2: constant velocity of zero (at rest)Object 3: constant velocity to the left or downward
12 Instantaneous Velocity Velocity at a single instant of timeSpeedometers in cars measure instantaneous speed.Determined by finding the slope at a single point (the slope of the tangent)
13 0.98 m/s to the east Book Problems Heather and Matt take a 34 minute walk eastward along a straight road to a store 2.0 km away. What is their average velocity in m/s?0.98 m/s to the eastBook Problems
14 3.47 m/s to the south Book Problems Eugene is 75 km due south of Salem. If Joe rides from Salem to Eugene on his bike in 6.00 hr, what is his average velocity?3.47 m/s to the southBook Problems
15 20.83 m/s to the south Book Problems A bus traveled south along a straight path for 3.2 h with an average velocity of 88 km/h, stopped for 20.0 minutes, then traveled south for 2.8 h with an average velocity of 75 km/h. What is the average velocity for the total trip?20.83 m/s to the southBook Problems
16 490,000 m to the south Book Problems A bus traveled south along a straight path for 3.2 h with an average velocity of 88 km/h, stopped for 20.0 minutes, then traveled south for 2.8 h with an average velocity of 75 km/h. What is the displacement for the total trip?490,000 m to the southBook Problems