1-D Motion

Displacement, Position, and Distance

Velocity vs. SpeedFrame of Reference

Frame of Reference

x=0 x=1000 ft.x=975 ft.

Where is the grizzly?

Position vs. Displacement

x=0 x=1000 ft.x=975 ft.

Position depends upon your frame of reference.

Reference pointor origin

positions

Position vs. Displacement

x=0 x=1000 ft.x=975 ft.

If we change our frame of reference,

Reference pointor origin

positions

Then our positions change.

x=500 ft.x=475 ft.

Position vs. Displacement

x=0 x=1000 ft.x=975 ft.

Displacement is the difference in positions.

25 ft.

Position vs. Displacement

x=0 x=1000 ft.x=975 ft.

If we change our frame of reference,

25 ft.

the displacement stays the same.

Reference pointor origin

x=500 ft.x=475 ft.

1-D Motion

Displacement

Displacement is change in position.

1 0x x x Displacement can be positive or

negative.

Velocity

Average velocity is displacement in a given time.

1 0

1 0

displacement

timeintervalavg

avg

v

x xx dv

t t t t

Finding displacement from velocity and time.

The high-speed train travels from Paris to Lyons at an average velocity of +227 km/h. The trip takes 2.00 h. How far is Lyons from Paris?

Finding displacement from velocity and time.

Paris Lyons227 km/h

Dt=2h UnknownDx

xv

tx

t v tt

x v t

Finding displacement from velocity and time.

Paris Lyons227 km/h

Dt=2h UnknownDx

x v t

(227km/h)(2.00h)x

(454km)x