PHYSICS CHAPTER MOTION

 

                                         PHYSICS CHAPTER
                                                         MOTION


Que-1What is Motion?

We can define motion as the change of position of an object with respect to time. A book falling off a table, water flowing from the tap, rattling windows, etc all exhibit motion. Even the air that we breathe exhibits motion! Everything in the universe moves. 

• Distance
• Displacement
• Speed
• Time

Types Of Motion

• Linear Motion
• Rotary Motion
• Oscillatory Motion

Linear Motion

In linear motion, the particles move from one point to another in either a straight line or a curved path. The linear motion depending on the path of motion is further divided as follows

• Rectilinear Motion – The path of the motion is a straight line.
• Curvilinear Motion – The path of the motion is curved.

Rotatory Motion

Rotatory motion is the motion that occurs when a body rotates on its own axis.  A few examples of the rotatory motion are as follows:

• The motion of the earth about its own axis around the sun is an example of rotary motion.

Oscillatory Motion

Oscillatory motion is the motion of a body about its mean position. A few examples of  oscillatory motion are

• When a child on a swing is pushed, the swing moves to and fro about its mean position.
• The pendulum of a clock exhibits oscillatory motion as it moves to and fro about its mean position.

  Que-2 Difference between uniform and nonuniform motion?

Uniform motion 1) If an object covers equal distance in equal interval of time the the motion is said to be uniform motion. 2) We can depect the uniform motion by Distance-time graph which shows staight line. 3)Uniform motion implies the movement of a body along a straight line with steady speed. 4) Zero acceleration

Non-Uniform motion 1) If an object covers unequal distance in equal interval of time then the motion is said to be Non-Uniform motion. 2) We can depect the Non-Uniform motion by Distance-time graph which shows a curved line. 3)Non-uniform motion alludes to the movement of an object along a straight line with variable speed. 4) Non-zero acceleration

Que-3 Define Average Speed & average velocity with its formula?

Average Speed
The average speed of a body in a certain time interval is the distance covered by the body in that time interval divided by time. So if a particle covers a certain distance s in a time t1 to t2, then the average speed of the body is:

vav =_s_
          t2–t1

In general, average speed formula is:

Average Speed = Total Distance
                                Total Time

 

Average Velocity

The average velocity of a body in a certain time interval is given as the displacement of the body in that time interval divided by time. So if a particle covers a certain displacement AB−→−  in a time t1 to t2, then the average velocity of the particle is:

vav−→ = AB−
          →−t2–t1

In general, the  formula is:

Average Velocity= Total Displacement
                                  Total Time

Que-4 Write the equation of motion?

 

Equations of motion relate the displacement of an object with its velocity, acceleration and time. The motion of an object can follow many different paths. Here we will focus on motion in a straight line (one dimension). We can therefore just use positive and negative magnitudes of the displacement, velocity and acceleration, where negative values are in the opposite direction to positive quantities.

If there is no acceleration, we have the familiar formula:s, equals, v, t.  s=vtwhere s,s is the displacement, v,v the (constant) speed and t,t the time over which the motion occurred. 

Que-5 Equation for position time relation?

Let us assume,

s = distance travelled      

t = time t

a = uniform acceleration

Therefore, Distance travelled by the object is given by area enclosed with OABC in the graph.

Therefore, s = area OABC ( Which is a trapezium )

= ( area of rect. OADC ) + ( Area of tri.ABD )

= ( OA × OC ) +  ( AD × BD )

NOW SUBSTITUTE :-

OA = u,

OC = AD = t

And

BD = at

We get :-

s = ut +  ( t × at )

∴ s = ut + at²

 

Que-7 What is uniform circular motion?

UNIFORM CIRCULAR MOTION – DEFINITION: Uniform circular motion is defined as the motion of a particle along the circumference of a circle with constant speed.
UCM can also be defined as periodic motion of a particle moving along the circumference of a circle with constant speed.

e.g.
1. Motion of earth around the sun.
2. Motion of moon around the earth.