FRICTION FRICTION A force that resists motion or

FRICTION

FRICTION A force that resists motion (or tendency to move) between two objects in contact

Depends on 2 factors 1) The materials in contact 2) The normal force

Draw in the friction vector. Ff

Simulation Scroll down to find static friction animation.

Static friction force A force is applied but the object doesn’t move No motion = net force = 0 The friction force is in the opposite direction of the applied force Size of friction _______ the applied force

Static Friction FN Ff FA FW Net Force = Zero

Kinetic friction force Kinetic means : force is applied and the object moves but friction slows it down The friction force is in opposite direction to the motion The friction force is smaller than the applied force

Kinetic Friction Accelerating FN Ff FA FW Net Force ≠ Zero

Kinetic Friction Constant Velocity FN Ff FA FW Net Force = Zero

Friction equation Ff = μ F N FN =FW on a horizontal surface

Coefficients of Friction μs = coefficient of static friction μk = coefficient of kinetic friction

Air Resistance When an object moves through air it runs into air molecules. It is a type of friction because it resists the motion of the object.

A special situation Terminal velocity is when The object stops accelerating and travels at constant velocity. FAir = FW and Fnet = 0

A special situation FA FW

Terminal Velocity https: //www. youtube. com/watch? v=p 0 IZsfz. DS 4 s https: //www. youtube. com/watch? v=62 s. RY_B 7 kr. M Scroll down even more

Classwork/Homework Static Friction Problems