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A projectile is the name given to any body which once thrown into space with some initial velocity moves thereafter under the influence of gravity alone without being propelled by any engine or fuel. The path followed by a projectile is called its trajectory. Example- An object dropped from an aeroplane.

Adiabatic Processes

• Adiabatic is a process in which there is no heat flow takes place between the system and the surroundings.
• These processes are sudden.
• The walls of the container should be adiabatic
• For an adiabatic process of an ideal gas

An adiabatic occurs without transferring heat and mass between a thermodynamic system and it's surroundings

Addition of vectors satisfies two important properties.

• The commutative law, which states the order of addition doesn't matter: a+b=b+a. ...
• The associative law, which states that the sum of three vectors does not depend on which pair of vectors is added first: (a+b)+c=a+(b+c).
• Triangle law of vector addition states that when two vectors are represented as two sides of the triangle with the order of magnitude and direction, then the third side of the triangle represents the magnitude and direction of the resultant vector.

The earth is moving around the sun because the amount of gravity exerted by the sun is so much more than the Earth’s gravitational pull, the Earth is forced into an orbit around the sun. The sun’s gravity pulls the Earth toward it the same way it does to all the other planets in the solar system. It is similar to the way the Earth has captured the moon. Earth’s gravitational pull is far stronger than that of the moon, so the latter is forced into orbit around the former. But people know that gravity here on Earth causes objects to fall to the ground when dropped. They don’t orbit. Other forces are at work in space.

Why?

It is the form of energy which provides heat and power to operate a machine

Electricity is the flow of electrical power or charge

Don't use copy paste system plz

Circuit, cell, bulb, switch... Find out about the electrical terminology your primary-school child will be using in the classroom and try some hands-on activities to support learning about electricity at home. 

Electricity can be created in a variety of ways such as:

• burning fossil fuels (oil, gas, coal) at power stations,
• using wind power generated by wind turbines,
• using solar power generated by the sun,
• using water power (sometimes called hydropower) generated by running or falling water.

Electricity is transported to our homes, schools and places of work through wires and cables.

Electricity can also be stored in batteries (sometimes called cells). 

Ordered paired is a set in which the arrangement of any number or alphabet in accenting order

A pair of numbers in a specific order . For ex- (1,2) , (-4,12)

A derive force is a force which is either calculated using a mathematical process like using formulas and equations. It is a function of other more fundamental physical quantities.

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The forces which we see in our day to day life like muscular, friction, forces due to compression and elongation of springs and strings, fluid and gas pressure, electric, magnetic, interatomic and intermolecular forces are derived forces as their originations are due to a few fundamental forces in nature.

The coefficient of restitution (COR), also denoted by (e), is the ratio of the final to initial relative velocity between two objects after they collide. It normally ranges from 0 to 1 where 1 would be a perfectly elastic collision. The coefficient of restitution depends to a large extent on the nature of the two materials of which the colliding objects are made. It is also affected by the impact velocity, the shape and size of the colliding objects, the location on the colliding objects at which the collision occurs, and their temperatures.

m(12at^2-6bt)

From v=u+at,v_1​=0+at_1​

∴a = v_1​​/t₁​

F=ma=mv_1​​/t₁​​

Velocity acquired in t sec=at=v_1​​/t₁​ ​​t

Power=F×v= ​mv_1​​/t₁​ ×v_1​​/t₁​ ​t​=​mv₁²/ t₁²​t​

Bro contact no do na plz name ke sath

Supplementary units are the dimensionless units that are used along with the base units to form derived units in the International system. The class of supplementary contains only two purely geometrical units, that is the radian and the steradian.

Photons are electrically neutral. Photons have no mass, but they have energy E = hf = hc/λ. Here h = 6.626*10-34 Js is a universal constant called Planck's constant. The energy of each photon is inversely proportional to the wavelength of the associated EM wave. The energy associated with a single photon is given by E = h ν , where E is the energy (SI units of J), h is Planck's constant (h = 6.626 x 10–34 J s), and ν is the frequency of the radiation (SI units of s–1 or Hertz, Hz) 

2x/1+x^2

The inherent property of a material body by virtue of which it cannot change, by itself , its state of rest or of uniform motion in a straight line is called Inertia. DIFFERENT TYPES OF INERTIA:- 1) Inertia of rest - The tendency of a body to remain in its position of rest is called Inertia of rest. Example : A person standing in a bus falls backwards when the bus suddenly starts moving forward. When the bus moves , the lower part of his body begin to move along with the bus while the upper part of the body continue to remain in rest due to Inertia of rest. That is why , a person falls backwards when the bus starts. 2) Inertia of motion - The tendency of a body to remain in the state of uniform motion in a straight line is called Inertia of motion. Example : When a bus suddenly stops, a person sitting in it falls forward. As the bus stops, the lower part of his body comes to rest along with the bus while the upper part of the body continue to remain in the motion due to Inertia and fall forward. 3) Inertia of direction - The inability of the body to change by itself its direction of motion is called Inertia of direction. Example : When a bus takes a sharp turn, a person sitting in the bus experience a force acting away from the centre of the curved path due to his tendency to move in the original direction. He has to hold on a support to prevent himself from swaying away in the turning bus.

The tendency of a body to continue in its state of motion is called inertia of motion .
Example: Rider Falls forwards when a galloping horse stop suddenly. When the horse stops, the Rider on account of inertia of motion, continues moving and hence falls in forward direction.

Following are the different methods that are used for reducing the friction:

• For objects that move in fluids such as boats, planes, cars, etc, the shape of their body is streamlined in order to reduce the friction between the body of the objects as the fluid.
• By polishing the surface, as polishing makes the surface smooth and friction can be reduced.
• Using lubricants such as oil or grease can reduce the friction between the surfaces.
• When objects are rolled over the surface, the friction between the rolled object and surface can be reduced by using ball bearings

Angle of Friction beween any two surface in contact is defined as the angle which the resultant

of the force of limiting friction F_lim and normal reaction N makes with the direction of normal reaction N
as shown in figure. It is marked in the figure as θ.

The value of angle of friction depends on the material and nature of surfaces in contact. 

It can be seen from figure, tanθ = AC/OA = F_lim / N = μ , where μ is coefficient of limiting friction

The angle of repose or angle of sliding  α is defined as the minimum angle of inclination of a plane

with the horizontal such that a body placed on the plane just begins to slide down.

Its value depends on the material and nature of the surface in contact. 

from the figure it can be seen that, f =mg sinα ...............(1)

                                                        N = mg cosα ....................(2)

hence we get,  f / N = tan α = μ  

Frictional force causes a lot of losses in general upkeep and wear and tear of machinery. Hence it is considered as a evil. But almost all crucial tasks cannot be carried out without the presence of friction. Basic activities like walking and writing on a surface are possible due to friction. Hence it is considered as a necessary evil .