In short the Motion in a plane is the motion which occurs in two dimensions. Example is – Projectile motion or Circular motion. When we analyse such motions then there is two things we need to keep in mind one is- the origin and other is co-ordinates. That is Scalar and Vector quantities.
Projectile Motion: The motion which is experienced by the object or particle that is near the earths surface and it does move along a path that is curved and there is gravity that acts on it.The path is usually a parabola. It may also be a line when thrown directly upwards. This is known as Ballistics and such a trajectory is known as ballistic trajectory. If the force is acting from downwards then it is the gravity from earth and thus the body faces a downward acceleration.
Circular Motion: This is the movement of the object around the circumference of a circle or rotation around a circular path. This is uniform motion usually and there is constant angular rate of motion and speed is constant.
What is Motion: Basically Motion occurs when the body in question is displaced or moved or it changes its position. This is described in terms of displacement, distance or velocity or acceleration or speed and also it depends on time. When we observe a body in motion then we try to observe a body which is attached to a frame of reference for an observer. Here we observe the change in body position which changes to the frame of reference with time.
There is a branch of science which studies the motion of objects and it is called KINEMATICS. The branch of Science which studies forces and their effects on Motion is called DYNAMICS.
When we take an object which does not change its position in a given frame of reference then the object is said to be in a position of rest or it is considered immobile or in stationary phase. It has a constant or position with the surroundings. There is no frame of reference and thus the motion will not be calculated or determined. We see everything in this Universe to be in constant motion.
When talk of Motion it does apply to many objects like bodies, matter, particles, radiation particles or space time. Or motion of images or motion of shapes or boundaries.Thus Motion in general means that there is change in the position of the physical system in the space. If we talk of the motion of waves of quantum particles where configuration will apply to waves of particles that occupy the positions.
What is the main quality of body in motion– it is the momentum of the body. If we take an object which has momentum it will increase with the mass of the object and also along with its velocity. Here the total momentum will not change with time and this will not change until and unless there is an external force which acts on the body. This is the law of conservation of momentum.
Mechanics is a field which is based on the law of motion or Newton’s laws of Motion. Here the main things are the forces acting on the body and motion on that body. This was first compiled by Sir Isaac Newton in 1687 and he stated that:
When a body is at rest it will continue to be at rest until the body is acted upon by external forces. (LAW OF INERTIA)
For every action there is an equal and opposite reaction.
The force is equal to the change in momentum per change in the time period. IF a mass is constant then the force is equal to the mass times acceleration which means:
F= ma
Uniform motion: There is constant speed and the body moves in a particular direction at some regular intervals of time.
Oscillatory motion: This is the motion which repeats itself and is periodic. Here the object moves in equal time and due to a restoring force acting on it.
Rotationalmotion: Here the moving torque is balanced by the resting torque.
It is interesting to note that humans are also in constant motion. Apart from the constant movements of the various external body parts and locomotion humans are in motion in some ways that are difficult to understand. This is done by some special tools and observations. There are two reasons for this- One is Newton’s law of motion and lack of frame of reference which is obvious for humans to see if it is evident that humans are actually in some frame of reference or motion.
