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