1. Physics 111: Elementary Mechanics – Lecture 2 Carsten Denker NJIT Physics Department Center for Solar–Terrestrial Research

2. September 12, 2005Center for Solar-Terrestrial Research Introduction  Motion along a straight line Motion Position and displacement Average velocity and average speed Instantaneous velocity and speed Acceleration Constant acceleration: A special case Free fall acceleration

3. September 12, 2005Center for Solar-Terrestrial Research Motion Along a Straight Line  Everything moves!  Classification and comparison of motion  kinematics  Simplification Motion along straight line Forces cause motion Moving object is a particle or moves like a particle Displacement Displacement is a vector quantity. It has both a direction and magnitude!

4. September 12, 2005Center for Solar-Terrestrial Research Velocity  Average velocity  Average speed  Instantaneous velocity

5. September 12, 2005Center for Solar-Terrestrial Research Acceleration  Average acceleration  Instantaneous acceleration  Constant acceleration

6. September 12, 2005Center for Solar-Terrestrial Research Sample Problem II–2 An elevator is initially stationary, then moves upward (which we take the positive direction of x ), and then stops. Plot v as a function of time. (a)x(t) curve for an upward moving elevator cab (b)v(t) curve for the cab. Note v = dx/dt ! (c)a(t) curve for the cab. Note a =dv/dt !

7. September 12, 2005Center for Solar-Terrestrial Research Another Look at Constant Acceleration  Integration of acceleration  Indefinite integral or anti–derivative  Constant of integration You will learn about this in integral calculus!