2.  Frame of reference is a place or object that you assume is fixed  observations of how objects move in relation to that frame of reference.  perception of motion depends on the observers frame of reference. ◦ Humans usually use the earth as their frame of reference.

3. SCALAR  Tells magnitude (strength) only  Numerical in value  Ex: 8 m/s; 6.5 km/hr; 3.2 mi/hr  Speed is a scalar quantity VECTOR  Tells magnitude(strength) AND Direction  Numerical in value with direction  Ex: 8 m/s N; 6.5 km/hr SW; 3.2 mi/hr right  Velocity is a vector quantity

4. DISTANCE  How far an object has moved  Scalar quantity  Positive only  Units: meters (m) feet (ft) miles (mi) yards (yds) DISPLACEMENT  Where the object is in reference to starting point  Vector quantity  Can be positive or negative  Units: m N; mi SW; ft downstream; yds from home goal

5. displacement distance

6.  Scalar quantity  Formula: speed = distance s= d time t  Units: m/s; km/hr; mi/hr; cm/yr  Instantaneous speed: speed at any given moment  Average speed : total distance traveled over total time of travel Formula: avg speed =final distance – initial distance final time – initial time s avg = d f – d i t f - t i

7.  Vector quantity  Can have positive or negative values  Formula: velocity = displacement v= d time t  Units: m/s N; km/hr SW; mi/hr W  Changing directions while moving describes velocity NOT speed

8.  Vector quantity  Can be positive: moving forward, speeding up  Can be negative: moving backward, slowing down (deceleration)  Rate of change of an object’s velocity  Formula: acceleration = final velocity – initial velocity final time – Initial time a = v f – v i t f – t i Units: meter/sec/sec m/s 2 kilometer/hour/hour km/hrs 2