Chapter 3

3.1 Acceleration Non-uniform motion – more complex

Velocity-Time Graph  Useful to make  Consistent with position-time graph and motion map  Straight line versus curved line  Slope of line give acceleration Units m/s/s Rate of change of velocity

Graphs and Maps Position-time and velocity-time Motion map x (m) t (s) v (m/s)

Acceleration  Vector quantity  Avg a =  v/  t  Change in velocity over a time interval is average acceleration  Change of velocity in an instant is instantaneous acceleration Found by calculating slope of tangent at specific time on velocity-time graph  When would average and instantaneous be the same?

Motion maps  Show vectors on motion maps

Positive versus Negative  Assigning coordinate system is important  Deceleration is NOT a physics term

Kinematic curves  How are position-time, velocity-time and acceleration-time graphs connected?

3.2 Constant Acceleration  v f = v i + a avg  t  d f = d i + v i t f + ½ a avg t f 2  v f 2 = v i 2 + 2a avg  d

Graphs  Equations can be derived from equations  Displacement is area under velocity-time graph

3.3 Free Fall  Motion of object when air resistance is negligible and action considered due to gravity alone  Rock versus feather falling in air on earth On moon? On Jupiter?

Acceleration due to Gravity  All objects fall at the same rate on earth 9.80 m/s/s  What does the motion map for an object falling look like? x-t graph, v-t graph

Initial up, then down  Motion map  x-t graph  v-t graph  a-t graph

Lab  Newton’s 2 nd lab  Freefall lab, ch 3, pg 76-77