kinematics

• Number of degrees of freedom (NDOF) is the number of independent variables

  which should be specified to determine the position of all points in the system
• Tangential acceleration - the projection of the acceleration vector onto the velocity direction

  • The normal acceleration of the moving particle equals zero if, and only if, the path is a straight line
  • •The tangential acceleration = 0 if, and only if, the speed of the particle is constant .
• Normal acceleration - the projection of the acceleration vector onto the plane perpendicular to the velocity vector.

  • •The normal acceleration reflects the change in the direction of motion.
  • The normal acceleration =0 if, and only if, the path is a straight line
• constrained motion – the motion of the system is subjected to certain restraints
• A constraint of a system of material points or (and) rigid bodies – every restriction placed upon a motion of the system.