Download presentation
Presentation is loading. Please wait.
1
Chapter 2: Motion Along a Line
Position & Displacement Speed & Velocity Acceleration Describing motion in 1D Free Fall CQ: 1, 2, 3, 4. P:1, 11, 13, 25, 27, 29, 47, 50.
2
Applications Destination times
Design packing materials & road barriers Airbag deployment speed Simulations (movies & games)
3
Speed Speed = rate of travel at a given moment of time
Distance traveled = total length of the curved path
4
Initial/Final Notation
Same rules apply for all variables
5
Delta Notation called Displacement
6
Velocity (m/s) When Dt is small, Dx/Dt is the instantaneous velocity v.
7
Graphs Wilson (12) x vs t Giambattist (21) +, -, 0 accel.
8
Acceleration (m/s/s) If Dt is small, Dv/Dt is called the instantaneous acceleration and labeled “a”.
9
Ex. Car Acceleration from 10m/s to 15m/s in a time of 2.0 seconds.
from 10m/s to 15m/s in a time of 2.0 seconds. In this class we only use average acceleration and often drop the “avg” notation from acceleration.
10
Velocity Formula
11
acceleration Wilson (15) negative acceleration
12
Average Velocity with Uniform Acceleration
Uniform Acceleration = constant valued acceleration During uniform acceleration, average velocity is halfway between vo and v:
13
Average Velocity Formula
14
Displacement Formula
15
V-squared Equation
16
Kinematic Equations with Constant Acceleration
17
Ex. Human Acceleration In the 1988 Olympics, Carl Lewis reached the 20m mark in 2.96s (Bolt: 2.87s)
18
Ex: V2 Equation Approximate Stopping Accelerations in m/s/s:
Approximate Stopping Accelerations in m/s/s: Dry Road: ~ 9 (anti-lock) ~ 7 (skidding) Wet Road: ~ 4 (anti-lock) ~ 2 (skidding) At 60mph = 27m/s, what is the skid-to-stop distance on a wet road?
19
Scalars & Vectors Scalar: size only e.g. speed, distance, time
Vector: magnitude and direction e.g. displacement, velocity, acceleration In one-dimension the direction is determined by the + or – sign. In two-dimensions, two numbers are required.
20
Motion Diagrams Are velocity-position diagrams
Are velocity-position diagrams More visual than a graph of x or v vs. time Arrow gives direction, length represents the speed (use a dot for zero speed) (net) force required to change velocity Example: car speeding up to left
21
Free-Fall Acceleration
a = 9.8m/s/s in downward direction Ex. Speed of object dropped from rest after 1.0, 2.0, 3.0 seconds: v = vo at v(1.0s) = 0 + (-9.8)(1.0) = -9.8m/s v(2.0s) = 0 + (-9.8)(2.0) = -19.6m/s v(3.0s) = 0 + (-9.8)(3.0) = -29.4m/s /
22
Activities Moving Man phet animae Textbook type problems
23
Summary: speed: rate of travel average speed: distance traveled/time.
displacement: change in position velocity: rate position changes acceleration: rate velocity changes kinematic equation set free fall: constant acceleration. graphs and slopes
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.