1. Physics Section 2.1 Describe motion in terms of frames of reference, displacement and graphs
A frame of reference is a system for specifying the precise location of objects in space and time.
 An object is at rest (not moving) if its position does not change with respect to a fixed frame of reference.
An object that changes its position is said to have a displacement. A displacement is a change in position in a particular direction.
displacement Δx = xf – xi
Δx = displacement (m)
xi = initial position
xf = final position
∆x = 7 cm – 2 cm = 5 cm right

2. Difference between velocity and speed
average velocity vav= Δx = displacement = xf – xi Δt time tf – ti vav = average velocity (m/s) Δt = change in time (s) average speed = distance (no direction) time

3. Practice problems
Savannah walks with an average velocity of .98 m/s eastward. If it takes her 34 minutes to walk to the store, what is her displacement?
2. Davin drives his car with an average velocity of 48.0 km/h to the
east. How long will it take him to drive 144 km on a straight highway?

4. Constant velocity Variable velocity
Velocity Graphs The slope of the position-time graph is the velocity. The instantaneous velocity is the slope of the line tangent to the curve at a specific point. (time)
Constant velocity
Variable velocity

5. assignment
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Problems 1 - 6