Newton's Laws of Motion
Newton's First Law of Motion
Everybody remains in its state of rest or of uniform motion, unless it is compelled to change its state by an unbalanced force, impressed on it.
\[F=m\times a\]
if, \[F=0\]
\[\Rightarrow \,\,a=0\,\,(m\ne 0)\]
(i) We tend to fall forward when a bus suddenly stops. When bus stops suddenly, we tend to resist the change in our state of motion and hence fall forward.
(ii) We tend to fall backward when a bus suddenly starts.
(iii) We tend to get thrown to one side when a car takes sharp turn.
Martin and Robert are arguing in the cafeteria. Martin
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Distance - Time Graph for Uniform Motion
A public transport bus is traveling from terminus P to terminus Q. The following observation was recorded by a passenger in the bus..
Observations
Difference between Distance and Displacement
Introduction
In everyday life we always come across some objects which are at rest and some objects in motion. The branch of Physics, which deals with the behavior of moving objects, is known as mechanics. Mechanics is further divided into two sections namely Kinematics and Dynamics. Kinematics deals with the study of motion without taking into account the cause of motion, while Dynamics is concerned with the cause of motion, namely force. This chapter covers only the different aspects of motion without considering the cause of motion.
When we are sitting in a
Inertia
Inertia is the property of a body due to which the body opposes any change in its state of rest or of uniform motion along a straight line. Inertia is the measure of mass. More mass means more inertia.
Inertia of Rest
A body which is at rest will remain at rest unless or until some external force is applied to it.
It is the inability of a body to move on its own.
Activity
Classification of Forces
Forces may be classified into the following two classes:
Free Body Diagram
A book is at rest on a table top..
Introduction
The Greek thinker, Aristotle held the view that if a body is moving, something external -is required to keep it moving. The Aristotelian law of motion may be phrased for our purpose here, : An external force is required to keep a body in motion.
Effects of force
Bhor’s Model of Atom
After the drawback found in Rutherford model of an atom, it became necessary to find the reason for the stability of the atom. Bhor put forward his model of an atom and this was found to be acceptable to almost all the scientis of that time. According to Bhor model, an atom consists of nucleus which contains neutron and proton and electron that revolve around the nucleus in the fixed orbit and do not radiate energy. Energy is radiated or absorbed by an atom only when an electron moves from one shell to another. When electrons jumps from lower to higher energy level, it absorbs energy and when it jumps from higher to lower it radiates energy. The energy is always radiated or absorbed in the form of packet called photons. The orbit or the shell in
Rutherford's Alpha Particle Scattering Experiment
In his experiment Rutherford bombarded a thin gold foil with the fast moving alpha particles. He took a gold foil about 1000 atoms thick and a doubly charged helium ions.
Observation
In his experiment Rutherford made the following observation:
Thomson's Model of Atom
Thomson proposed the model of atom before the discovery of neutrons. According to his model, an atom consists of a positively charged sphere and electrons are embedded in it. The positive and negative charge are equal in magnitude that’s why atom is electrically neutral. His model was also known as watermelon model of an atom. Although Thomson's model was electrically neutral, but other scientist could not explain this model and hence was not accepted.
Drawback of Thomsons Model
Some of the drawbacks of Thompson's model of atom were:
