# MOTION

## MOTION , THERE DIFFERENT TYPES, AND EQUATIONS OF MOTION .

Motion –

Rest and Motion -An object is said to be in rest , if body does not change its position with time , with respect to surroundings . An object is said to be in motion , if body  changes its position with time , with respect to surroundings .

Motion of the body can be of following type

• Rectilinear / Translatory motion – In rectilinear motion a point mass body moves along a straight line . but in translator motion a body which is not a point mass moves in a straight line path.

• Circular or rotatory motion – In circular motion a point mass object moves on a circular path. But in rotatory motion a body which is not a point mass moves on a circular path .

• Oscillatory or vibratory motion– oscillatory motion is a type of motion in which a body moves to and fro or back and forth repeatedly about a fixed point. If in the oscillatory motion, amplitude is very small then the motion of the body is said to be in vibratory motion.

Motion in one , two and three dimensions-

• One dimensional motion– The motion of a body is said to be in one dimensional if only one co-ordinate specify the position of the object in the given time. In such a motion body moves along a straight line
• Two dimensional motion– The motion of a body is said to be in two dimensional if any two coordinate specify the motion of the body.
• Three dimensional motion – The motion of a body said to be in three dimensional if all three coordinates specify the motion of the body . in such kind of motion body may cover a specific motion or irregular motion.

UNIFORM AND NON-UNIFORM MOTION-

Uniform motion – If a body covers equal distance in equal interval of time then it is said the motion of a body is uniform .

Some important features of the uniform motion is following-

(a) For a uniform motion  along a straight line in a given direction , the distance and magnitude of the displacement remain the same .

(b) The velocity in uniform motion doesn’t depend upon the time interval .

(c)There is no need of force for an object to be in uniform motion .

(d) The velocity in uniform motion is in dependent of choice of origin.

(e) The average and instantaneous velocities have value in uniform motion.

If the motion of the object is uniform the following formula is used to find the

different– different physical quantities .

Distance = speed x time ;    speed = distance / time

Displacement = velocity x time ;   Velocity = displacement / time ;

Average speed = total distance covered / total time taken .

Average velocity = total displacement covered / total time taken

V =  X2-X1 / t2-t1 .

Non-uniform motion- An object is said to be in non-uniform motion if it covers unequal distance in equal interval of time ,or equal distance in unequal interval of time. The velocity of a body changes with time it may increase ( accelerated ) or decrease (deaccelerate) with time .

Following are the important equations of motion– for uniformly accelerated motion

• 1st of motion ( it is also known as velocity – time relation)- v = u + at ( Where v=final velocity, u= initial velocity , a= acceleration, t = time taken .)
• 2nd of motion (it also known as distance – time relation ) – S=ut+1/2 at2 (where s=displacement ;  u = initial velocity ; a= acceleration ; t = time taken .)
• 3rd of motion (it is also known as the velocity- position relation) – V2-U2=2aS (where – S= displacement ; V= final velocity ; U= initial velocity ; a= acceleration .)

TO SEE THE VIDEO FOR THE DERIVATION OF ALL THREE EQUATIONS OF MOTION CLICK HERE-

• 4th of motion ( distance covered by the body in nth second ) Snth = u+ a(2n-1)/2 . (where Snth = distance covered in nth second ; a= acceleration ; n= given time ; u= initial velocity .)

TO SEE THE VIDEO FOR THE DERIVATION OF 4th EQUATION OF MOTION CLICK HERE-