Question

what are the Newton's laws of motion??

Answer 1

please mark as brainliest
say thanks




(1). Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This is normally taken as the definition of inertia. The key point here is that if there is no net force acting on an object (if all the external forces cancel each other out) then the object will maintain a constant velocity. If that velocity is zero, then the object remains at rest. If an external force is applied, the velocity will change because of the force.

(2). The second law explains how the velocity of an object changes when it is subjected to an external force. The law defines a force to be equal to change in momentum (mass times velocity) per change in time. Newton also developed the calculus of mathematics, and the "changes" expressed in the second law are most accurately defined in differential forms. (Calculus can also be used to determine the velocity and location variations experienced by an object subjected to an external force.) For an object with a constant mass m, the second law states that the force F is the product of an object's mass and its acceleration a:

F = m * a

For an external applied force, the change in velocity depends on the mass of the object. A force will cause a change in velocity; and likewise, a change in velocity will generate a force. The equation works both ways.

(3). The third law states that for every action (force) in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exerts an equal force on object A. Notice that the forces are exerted on different objects. The third law can be used to explain the generation of lift by a wing and the production of thrust by a jet engine.

Answer 2

Hi

Here is your answer,

                                NEWTON'S LAW OF MOTION

Sir Issac Newton (1664 - 1727) made a systematic study of motion and extended the views of Galileo. He arrived at three laws of motion which are called Newton's law of motion. 

                            NEWTON'S FIRST LAW OF MOTION

This law states that everybody continues in its states of rest or of uniform motion in a straight line unless it is compelled by some external force to change that state.

The state of rest or uniform linear motion both imply zero acceleration. The first law of motion can therefore by simply expressed as:

If the net external force on a body is zero, its acceleration is zero, Acceleration can be non-zero, only if there is a net external force on the body.


                       NEWTON'S SECOND LAW OF MOTION

This law states that the rate of change of momentum of a body is directly proportional to the external force applied on the body and the change take place in the direction of the applied force.

Let F be the external force applied on the body in the direction of motion of the body for time internal Δt, then the velocity of a body of mass m changes from v to v + Δv change in momentum Δp = mΔv. 

According to Newton's second law,

                   F  Δp/Δt  or F = k Δp/Δt

where k is a constant of proportionality 

If limit Δt = 0 then the term Δp/Δt becomes the derivative dp/dt

Thus,                  F = k dp/dt 

For a body of fixed mass m,

                            F = k d(mv)/dt = km dv/dt

               F = kma                                               ( ∴ dv/dt = a )

Let k = 1

Force, F = ma
 
In scalar form, this equation cab be represented as
 
         F = ma

∴ 1 unit force = 1 unit mass × 1 unit acceleration 


                         NEWTON'S THIRD LAW OF MOTION

When we press a coiled spring, is compressed by the force our hand. In turn, the compressed spring exerts a force on our hand, and we feel it. Also, the earth pulls a stone downward due to gravity. But according to Newton, the stone exerts an equal and opposite force on the earth. The earth is very massive and the effect of a small force on its motion is negligible.

Thus, forces always occurs in pairs as a result of mutual interaction between two bodies.

Newton's third law states that for every action, there is always an equal and opposite reaction.

Now, we can state the third law in a simple way. 

See, Force is nature always occurs in pairs. Force on a body A by body B is equal and opposite to the force on the body B by A.

Now, I will give you some important implications about the 3rd law of motion.

(1) Newton's 3rd law of motion is applicable irrespective of the nature of the forces. The forces of action ans reaction may be mechanical, gravitational, electric or of any other nature.

(2) Action ans reaction always acts on two different bodies. If they acted on the same body, that resultant force would be zero and there could never be accelerated motion.

(3) The force of action and reaction cannot cancel each other this is because action and reaction, though equal and opposite force always acts on different bodies and so cannot cancel each other.

(4) No action can occur in the absence of a reaction.

I will explain this sentence by a small example:- 

In a tug of war, one team can pull the rope only if the other team is pulling the other end of the rope, no force ca n be exerted if the other end is free.

One team can exert the force of action because the other team provides the force of reaction.



Hope it helps you !