Newtonian Physics Definition Cheat Sheet

Kinematics
Displacement	It is the shortest linear distance of the position of a moving object from a given reference point.
Speed	It is the rate of change of distance travelled with respect to time.
Velocity	It is the rate of change of displacement with respect to time.
Acceleration	It is the rate of change of velocity with respect to time. Its direction is that of velocity change.
Dynamics
Newton’s First Law of Motion	It states that a body will continue in its state of rest or uniform motion in a straight line unless an external force acts on it.
Newton’s Second Law of Motion	It states that the rate of change of momentum of a body is directly proportional to the resultant force acting on it and takes place in the direction of the resultant force.
Newton’s Third Law of Motion	It states that if body A exerts a force on body B, then body B exerts a force of the same type that is equal in magnitude and opposite in direction on body A.
Mass	The property of a body that resists a change in motion.
Weight	The force acting on a body due to a gravitational field.
Linear Momentum	It is defined as the product of the mass and its velocity. The direction of linear momentum is same as its velocity.
Impulse	It is the product of a force F acting on an object and the time t for which the force acts.
Force	It is the rate of change of momentum and acts in the direction of the change in momentum.
Principle of Conservation of Momentum	It states that the total momentum of a system of objects remains constant provided no resultant external forces acts on the system.
Perfectly Elastic Collision	For a perfectly elastic collision between two bodies, the relative speed of approach is equal to the relative speed of separation due to the conservation of total kinetic energy of the two particles.
Head-on Collision	The particles will move in a straight line with respect to each other after collision.
Hooke’s Law	It states that within the limit of proportionality, the extension produced in a material is directly proportional to the load applied.
Upthrust	It is an upward force on a body immersed in a fluid due to the pressure difference in a fluid.
Centre of Gravity	The weight of a body that may be taken as acting at a single point.
Couple	It is a pair of forces parallel and opposite in direction which tends to produce rotational motion only.
Moment of a Force	It is the product of the force and the perpendicular distance of the line of action of the force from the point.
Torque of a Couple	It is the turning effect of the couple; product of one of the forces and the perpendicular distance between their lines of action of force.
Equilibrium	No resultant force and no resultant torque.
Archimedes’ Principle	It states that when a body is totally or partially immersed in a fluid, it experiences an upward force (upthrust) equal to the weight of fluid displaced.
Principle of Flotation	For an object floating at equilibrium, the upthrust is equal to the weight of the object.
Work done by a force	Product of a force and the displacement in the direction of the force.
Principle of Moments	If a body is in equilibrium, the sum of all clockwise moments about any axis must be equal to the sum of anti-clockwise moments about the same point.
Pressure	The force per unit area, where the force is acting at right angles to the area.
Work, Energy, Power
Efficiency	It is the ratio of the work gotten out of a machine to the energy put in.
Power	The work done per unit time.
Watt	It is the amount of power when the work done per unit time is one joule per second.
Circular Motion
Angular displacement	It is the angle through which the object turns.
Radian	One radian is the angular displacement when the arc length is equal to the radius of the circle.
Angular Velocity	It is the rate of change of angular displacement with respect to time.
Gravitational Fields
Gravitational Field	It is a region of space where a mass experiences a force. The direction of field is the direction of force on the mass.
Field of force	It is a region of space that can be mapped with lines of force and lines of potential.
Gravitational Field Strength	It is the force per unit mass acting on a small mass placed at that point in the gravitational field.
Newton’s Law of Gravitation	It is the mutual force of attraction between two point masses and is directly proportional to the product of the masses and inversely proportional to the square of the distance between the centre of both masses.
Gravitational Potential at a Point	It is the work done per unit mass in bringing a point mass from infinity to that point.
Gravitational Potential energy	The gravitational potential energy of the mass at a point is the work done on the mass in moving it from infinity to that point.
Geostationary satellite	It is a satellite which remains above a fixed point above Earth’s surface. It orbits the Earth in exactly one day and lies in the place containing the equator and moves from West to East.