1. Grades:  Individual Grade: 100 - 3* (Lost points in the corresponding section)  Example: Group Grade: 80  PI lost 10 points = 100-3*10=70  Data lost 3 point= 100-3*3=91  Researcher lost 7 points=100-3*7=79

2. Attention!  If you see problems or mistakes in report you should report it to your group for correction  Data analysists should inform PI when they see something wired during experiment. So, the PI will not make a wrong conclusion base on the incorrect data and you will not lose any point in conclusion.

3. Acceleration  The acceleration of the car does not depend on the initial and final velocities. If you saw the different values in your measurements, they are caused by measurement error.  F=Ma : Acceleration is only dependent on the forces applying to the object.  Gravitational acceleration is not depenent on any thing is roughly g=9.8 m/s 2  If a force changes, the acceleration of the object changes.

4. Acceleration and Friction  Is there any force acting of the object?  Yes: accelerates  No: moving with constant speed or sum of forces acting on the object is zero  Friction force is a kind of force acting on objects: Relation: F(friction)=µ*F N What is Normal force: F N =Mg It does not depend on the velocity of the car or direction of the motion

5.  Static Friction Force ------------- Static Friction Coefficient µ s  Kinetic Friction Force ------------ Kinetic Friction Coefficient µ k