perpendicular to sliding surfaces

along sliding surfaces

somewhere in between above two

unpredictable

leads the sliding velocity vector by 90°

lags the sliding velocity vector by 90°

is along the sliding velocity vector

leads the sliding velocity vector by 180°

crank has a uniform angular velocity

crank has non-uniform velocity

crank has uniform angular acceleration

crank has uniform angular velocity and angular acceleration

velocity of various parts

acceleration of various parts

displacement of various parts

angular acceleration of various parts

pitch circle

base circle

prime circle

outer circle