We have seen the various types of motions which may be undergone by particles and rigid bodies. You may be able to understand the relationships of displacement, velocity and acceleration while a particle is moving along a straight path. The acceleration of the particle can be uniform or may be variable. A special type of linear motion called simple harmonic motion is also studied by you and we are aware that this is a repetitive type of motion.
A particle can move along a circular path with uniform or variable velocity. We have studied the methods by which we can calculate tangential and normal components of accelerations. A special type of curvilinear motion is called as projectile in which the path is parabolic and is called as trajectory.
A rigid body motion can be translatory or rotational about a fixed axis and can cause velocity and acceleration at different points in the body. A plane motion is a combination of these two motions. To calculate velocity in plane motion we may use instantaneous centre technique velocity diagram method. Furthermore, acceleration in plane motion can be calculated if we know the angular acceleration of the body.
Several times, the axes of reference are not fixed. The same are connect to a body called vehicle which moves and observations are built by the observer standing on the vehicle. Thus relative motion and relative velocity can be calculated.
The kinematics part of dynamics of bodies is extremely important for understanding the motions and the forces which are responsible for causing the motions.