1. Physics 111: Elementary Mechanics – Lecture 4 Carsten Denker NJIT Physics Department Center for Solar–Terrestrial Research

2. September 26, 2005Center for Solar-Terrestrial Research Newton’s Laws I.If no net force acts on a body, then the body’s velocity cannot change. II.The net force on a body is equal to the product of the body’s mass and acceleration. III.When two bodies interact, the forces on the bodies from each other are always equal in magnitude and opposite in direction.

3. September 26, 2005Center for Solar-Terrestrial Research Static & Kinetic Friction Static frictional force Kinetic frictional force Skid marks are 290 m long!  k = 0.6 and a = const. How fast was the car going when the wheels became locked?

4. September 26, 2005Center for Solar-Terrestrial Research Drag Force and Terminal Speed Drag force Terminal speed Drag coefficient C, air density , and effective cross-section A.