1. Forces, Forces Everywhere An investigation of frictional forces around us

2. Forces Newton’s 2 nd law: F=m*a – Weight is an example of Force – Gravity is an example of Acceleration Forces can be described by the direction in which the acceleration acts Forces acting on surfaces – Normal Force

3. “Nonconservative” Forces Friction – Proportional to the normal force – Exists for motionless and moving objects. – F f =μN Drag – Proportional to velocity of fluid or object – F d =(½)ρv 2 C d A Density, velocity, drag coefficient, area

4. Purpose We will experiment with friction by examining the force needed to move two surfaces past each other, and analyze the force-position data to calculate frictional coefficient(s).

5. Hypothesis **Think about these questions** Will the roughness of the wheels and sliding surface (floor) have an effect on the force required to move the car? How are we comparing surface roughness?