SECOND LAW OF MOTION FREE

For a constant mass, force equals mass times acceleration. Rockets work by producing a strong reaction force downwards using rocket engines. Newtons second law of motion states that Force is equal to the rate of change of momentum. Third To every action, there is always opposed an equal reaction or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts. Newton's second law has also been regarded as setting out a research program for physics, establishing that important goals of the subject are to identify the forces present in nature and to catalogue the constituents of matter. If the body's location as a function of time is s ( t ) into Newton's second law, an equation with predictive power can be written.

SECOND LAW OF MOTION FREE

For example, a body might be free to slide along a track that runs left to right, and so its location can be specified by its distance from a convenient zero point, or origin, with negative numbers indicating positions to the left and positive numbers indicating positions to the right. Its position can then be given by a single number, indicating where it is relative to some chosen reference point.

The simplest case is one-dimensional, that is, when a body is constrained to move only along a straight line. Movement is represented by these numbers changing over time: a body's trajectory is represented by a function that assigns to each value of a time variable the values of all the position coordinates. The mathematical description of motion, or kinematics, is based on the idea of specifying positions using numerical coordinates. For instance, the Earth and the Sun can both be approximated as pointlike when considering the orbit of the former around the latter, but the Earth is not pointlike when considering activities on its surface. This is a reasonable approximation for real bodies when the motion of internal parts can be neglected, and when the separation between bodies is much larger than the size of each. Figure 5.4.1: Different forces exerted on the same mass produce different accelerations. This concept is revisited many times in the study of physics. Newton's laws are often stated in terms of point or particle masses, that is, bodies whose volume is negligible. The concept of a system is fundamental to many areas of physics, as is the correct application of Newton’s laws. Limitations to Newton's laws have also been discovered new theories are necessary when objects move at very high speeds ( special relativity), are very massive ( general relativity), or are very small ( quantum mechanics). In the time since Newton, the conceptual content of classical physics has been reformulated in alternative ways, involving different mathematical approaches that have yielded insights which were obscured in the original, Newtonian formulation. Newton used them to investigate and explain the motion of many physical objects and systems, which laid the foundation for classical mechanics.

The three laws of motion were first stated by Isaac Newton in his Philosophiæ Naturalis Principia Mathematica ( Mathematical Principles of Natural Philosophy), originally published in 1687. If two bodies exert forces on each other, these forces have the same magnitude but opposite directions.When a body is acted upon by a force, the time rate of change of its momentum equals the force.A body remains at rest, or in motion at a constant speed in a straight line, unless acted upon by a force.These laws can be paraphrased as follows: With the vector notation indicating that the net external force is in the same direction as acceleration.Newton's laws of motion are three basic laws of classical mechanics that describe the relationship between the motion of an object and the forces acting on it.

Second law of motion