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Explain translatory motion and give examples of various types of translatory motion.
Translatory motion:
In translation motion, a body moves along a line without any rotation. The line may be straight or curved.
Examples:
Riders moving on the Ferris wheel are also in translational motion. Their motion is in a circle without rotation.
Types of Translatory motion:
Translatory motion can be divided into linear motion, circular motion, and random motion.
1. Linear motion:
The straight-line motion of a body is called linear motion.
Examples:
The motion of objects such as a car moving on a straight and level road is linear motion.
Airplanes flying straight in the air and objects falling vertically down are also examples of linear motion.
2. Circular motion:
The motion of an object in a circular path is called circular motion.
Examples:
A stone tied at the end of a string can be made to whirl. The stone moves in a circle and thus has a circular motion.
Toy train moving on a circular track. A bicycle or a car moving along a circular track possess circular motion.
The motion of the earth around the sun and the motion of the moon around the earth are also examples of circular motion.
3. Random Motion:
The disordered or irregular motion of an object is called random motion.
Examples:
The motion of insects and birds is irregular. Thus, the motion of insects and birds is random
The motion of dust or smoke particles in the air is also random.
The Brownian motion of a gas or liquid molecules along a zigzag path as shown in the figure is also an example of random motion.
Define the terms speed, velocity and acceleration
Speed:
The distance covered by an object in unit time is called speed.
$Speed = \frac{Distance \: covered}{Time \: taken}$
$v = \frac{S}{t}$
Velocity:
The rate of displacement of a body is called velocity.
$Velocity=\frac{Displacement}{Time \: taken}$
$v = \frac{D}{t}$
Acceleration:
Acceleration is defined as the rate of change of velocity of a body
$acceleration = \frac{Change \: of \: velocity}{Time \: taken}$
$acceleration = \frac{final \: velocity \: - \: initial \: velocity}{Time \: taken}$
$a=\frac{vf \: - \: vi}{t}$
Unit of acceleration:
SI unit of acceleration is a meter per second square.
Differentiate between the following:
(i) Rest and motion
(ii) Circular motion and rotatory motion
(iii) Distance and displacement
(iv) Speed and velocity
(v) Linear and random motion
(vi) Scalers and Vectors
1. Difference between Rest and motion:
Rest:
A body is said to be at rest if it does not change its position concerning its surroundings.
Motion:
A body is said to be at rest if it changes its position concerning its surroundings.
The state of rest or motion of a body is relative. For example, a passenger sitting in a moving bus is at rest because he/she is not changing his/her position concerning the other passengers or objects in the bus but to an observer outside the bus the passengers and the objects inside the bus are in motion
2. Difference between Circular and rotatory motion:
Circular motion:
Any turning as if on-axis is rotatory motion. Any rotatory motion where the radius of gyration, length, and axis of rotation is fixed is circular motion. And that is the difference. Circular motion is just a special case of rotatory motion. That is, there is no fixed axis and radius restriction for rotatory motion. But there is circular motion.
For example, all planets have rotatory motion around their suns but most of the orbits are elliptical. Therefore, the rotation axis and radius of gyration vary as they trek around. So, most, if not all, planets do not have circular motion.
Note: Gyration length:
A length that represents the distance in a rotating system between the point about which it is rotating and the point to and from which the transfer of energy has the maximum effect.
3. Difference between distance and displacement:
|
Distance |
Displacement |
|
Length of the path between two points is called the distance between those points. |
Displacement is the shortest distance between two points which has magnitude and direction distance distance |
|
Distance is a scalar quantified displacement |
Displacementquantity distancentity |
|
Distance is denoted by “S”. S=vt Its unit is metered (m). |
Displacement is denoted by “d”. d=vt Its SI unit is meter (m). |
|
Distance(S) dotted lines, Displacement(d) dark lines from point A to B. |
|
4. Differentiate between speed and velocity
|
Speed |
Velocity |
|
The distance covered by an object in a unit of time is called speed.
Distance=speed x time Or S=vt |
The rate of displacement of a body is called velocity.
V=d/t or d=vt |
|
Speed is a scalar quantity. |
Velocity is a vector quantity. |
|
SI unit ispeed is |
SI unit of velocity is the same as the speed |
5. Difference between linear and random motion
Linear motion:
The straight-line motion of a body is called linear motion.
Examples:
The motion of objects such as a car moving on a straight and level road is linear motion.
Airplanes flying straight in the air and objects falling vertically down are also examples of linear motion.
Random Motion:
The disordered or irregular motion of an object is called random motion.
Examples:
The motion of insects and birds is irregular. Thus, the motion of insects and birds is random.
The motion of dust or smoke particles in the air is also random.
The Brownian motion of a gas or liquid molecules along a zigzag path as shown in the figure is also an example of random motion.
6. Difference between scalers and vectors:
|
Scalers |
Vectors |
|
A scalar quantity is described completely by its magnitude only. |
A vector quantity is described by its magnitude and direction. |
|
Examples Examples of scalers are mass, length, time, speed, volume, work, energy, density, power, charge, pressure, area, and temperature. |
Examples Examples of the vector are velocity, displacement, force, momentum, torque, weight, electrical potential, etc. |
