Motion in 1 DimensionPhysics: Chapter 2-1

Pages 40-47

Displacement Displacement- length of the straight line

drawn from initial position to final position.

Change in position of an object

Measured in meters (or km, cm, etc.)

Displacement

Displacement ≠ distance traveled

DisplacementCoordinate systems used to describe

motion (x, y, z)

xi = initial position

xf = final position

Horizontal = x-axis (Δx) Vertical = y-axis (Δy)

DisplacementDisplacement = change in position = final position – initial position

Δx = change (delta) in x-axis

∆x = xf – xi

Δy = yf – yi

DisplacementA point of reference is arbitrarily chosen,

but the same point must be used through the problem

Displacement can be positive or negative

* has magnitude & direction (+ or -) for consistency to right to left

VelocityVelocity – change in displacement during

a given time interval in a certain direction

Measured in meters per second (m/s)

Velocity Average velocity = change in position = displacement change interval time interval

V avg = Δx = Xf – Xi

Δ t tf – ti

VelocityVelocity ≠ speed Velocity has magnitude & directionSpeed has magnitude, no direction

Graphing Velocity Velocity can be

interpreted graphically

Displacement is measured over time at specific intervals

When points plotted on a graph, the

slope = average velocity

Graphing VelocitySlope = rise = change in vertical coordinate run change in horizontal coordinates

V avg = Δx = Xf – Xi

Δ t tf – ti

Graphing VelocitySteeper slope = larger velocityHorizontal slope = no velocity (object

at rest)