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Showing posts with label education. Show all posts ## What Is The Difference Between Speed And Velocity And Acceleration?

Speed, velocity and acceleration describe the motion of a body but there is a difference between speed, velocity and acceleration. The rate at which a body move is known as its speed. We can define speed as distance travelled by a body in unit time is known as its speed. On the other hand, the velocity of a body tells us how fast a body is moving in a particular direction. We can define velocity as the time rate of change of displacement of a body is known as velocity. If we talk about acceleration, we come to know that the time rate of change of velocity is known as acceleration. Here, we will briefly explain speed, velocity and acceleration. After reading this article, you will clearly understand the difference between speed, velocity and acceleration.

## What is speed?

As we have discussed earlier that distance travelled by a body in unit time is known as its speed. It is a scalar quantity because it is completely described by its magnitude and we don’t require direction to describe it. If the speed of an object is higher, it means that it moving at a faster rate. If the speed of an object is lower, it means that it is moving at a slower speed. As an SI unit of distance is ‘m’ and SI unit of time is ‘s’, therefore, the SI unit of speed is ‘m/s’.

## Formula to calculate the speed

We can easily calculate the speed of an object by using the following formula;
r= d/t
Here, r is known as speed, d is known as distance travelled and t is known as the time taken to travel this distance.

## Numerical relevant to speed

A cyclist covers a distance of 200 meters in 20 seconds, find out its speed.
Solution:
Distance travelled by the cyclist = 200 meters
Time taken to travel this distance = 20 seconds
Speed = Distance / Time
Speed = 200/20
Speed = 10 m/s

## What is velocity?

The time rate of change of displacement is known as velocity. The velocity of a body tells us how fast a body is moving in a particular direction. Therefore, velocity is a vector quantity because there requires magnitude as well as direction for its complete description. SI unit of velocity is m/s.

## Uniform velocity

If a body covers equal displacement in equal intervals of time, its velocity is known as uniform velocity. Graph of uniform velocity gives us a straight line.

## Variable velocity

If a body covers unequal displacement in equal intervals of time, its velocity is known as variable velocity. Graph of variable velocity doesn’t give us a straight line.

## Formula to calculate the velocity

We can calculate the velocity of an object by using the following formula;
Velocity = Displacement / Time

## Numerical relevant to velocity

If a man walks 300 m East in 100 seconds, find out its velocity?
Solution:
Displacement = 300m  ,    Time  = 100 seconds
Velocity = Displacement / Time
Velocity = 300/100
Velocity = 3 m/s

# Difference between speed and velocity

After getting an idea about speed and velocity, we are able to compare these two quantities. The main difference between speed and velocity is explained below;
1)    The first difference between speed and velocity is in their meanings. The meaning of speed is the distance covered by a body in unit time, whereas, the meaning of velocity is the displacement covered by a body in unit time.
2)    Speed of a body tells us how fast a body is moving. On the other hand, the velocity of a body tells us how fast and in which direction a body is moving.
3)    Speed is a scalar quantity because we don’t require direction for its complete description. Velocity is a vector quantity because there requires magnitude as well as direction for its complete description.
4)    Speed of an object is always positive. On the other hand, the velocity of an object can be positive as well as negative.

# What is the acceleration?

The time rate of change of velocity is known as acceleration. Acceleration is a vector quantity because there requires magnitude as well as direction for its complete description. If the velocity of a body is increasing, its acceleration is positive. On the other hand, if the velocity of a body is decreasing, its acceleration is negative. Unit of acceleration is meter per Second Square. Formula to find out the acceleration of an object is given below;
Acceleration = Velocity / Time

# Uniform acceleration

If the velocity of an object is the same in equal intervals of time, its acceleration is known as uniform acceleration. If we draw a graph between velocity and time, we get a straight line.

# Variable acceleration

If the velocity of an object is changing in equal intervals of time, its acceleration is known as variable acceleration. If we draw a graph between velocity and time, we can’t get a straight line.

# Numerical relevant to acceleration

If a car starts from zero and gains a velocity of 36km/h after 20 seconds, find out its acceleration.
Solution:
As we know that km/h is not the SI unit of velocity, therefore, before solving it, we have to convert it into an SI unit that is m/s.
Velocity = 36km/h = 10 m/s
Time = 20 seconds
Acceleration = Change in velocity / time
Acceleration = 10 – 0 / 20
Acceleration = 0.5 meter per second square

# Difference between velocity and acceleration

While studying motion, we have to come across with velocity and acceleration. Most of the students are not able to understand the difference between velocity and acceleration. The key difference between velocity and acceleration is given below;
1)    There is a difference between the meanings of velocity and acceleration. The velocity of an object is implied on the speed of an object. On the other hand, acceleration of an object is implied on the change in the velocity.
2)    There is also a difference between the definitions of velocity and acceleration. We define velocity as the rate of change in displacement. On the other hand, the acceleration of an object is defined as the time rate of change in velocity.
3)    The velocity of an object tells us the speed and moving direction of an object. On the other hand, the acceleration of an object tells us how the velocity of an object is changing.
4)    We can find the velocity of an object by dividing displacement over time. On the other hand, we can find acceleration by dividing velocity over time.
5)    Unit of velocity is meter per second and unit of acceleration is meter per Second Square.

## What is the difference between mass and weight?

Mass and weight are two commonly used terms in Physics. In the beginning, most of the students think that mass and weight are synonyms of each other. It is not a fact because mass and weight are two different terms because mass is known as the property of a body and weight is force acting on a body. In order to clearly understand the difference between mass and weight, we have to take an overview of different parameters.

## Difference between mass and weight

Mass and weight are different from each other on the basis of different parameters. Here, we compare these parameters one by one.

## Difference between definitions of mass and weight

Mass is known as the property of the matter and with the help of mass, we can easily measure the strength of the gravitational attraction of a body. On the other hand, weight is the amount of force that is acting on the body. This force can acts on a body either due to gravity or any kind of the reaction force.
Difference between their quantities

As we know that there are two types of physical quantities. First is the scalar quantity and the second is a vector quantity. There is also a clear difference between vector and scalar quantities. Mass of an object is a scalar quantity. Its reason is that to measure the mass of an object, we just need magnitude and unit. On the other hand, the weight of an object is a vector quantity because if we want to measure the weight of an object, we need its magnitude, unit and direction.
Difference between values of mass and weight
We can also observe a clear difference between the values of these two terms. The value of mass is the same at all the places because it doesn’t depend upon gravity. Therefore, we can say that the mass of an object can never be zero.
Conversely, weight of an object depends upon gravity. Therefore, it has different values in different places. For example, the weight of an object has two different values at Earth and Moon due to the difference in the values of gravity at Earth and Moon. On the other hand, the mass of an object remains the same on the Earth as well as on the Moon.
Different values at different locations
If we change the location of an object, we can’t see any kind of difference in the mass of an object. On the other hand, if we change the location of an object, we can see a definite difference in the weight of an object. If we going higher and higher, the value of gravity will decrease. As a result, the weight of an object also decreases. Conversely, if we are decreasing our altitude, the value of gravity will increase and we see a definite increase in the value of the weight of an object.
The difference between measuring instruments of mass and weight
It is a fact that if we are going to measure anything, we require a measuring instrument. In a similar way, either we are going to measure the mass of an object or weight of an object, we require measuring instruments. As mass and weight are two different terms, therefore, there require two different measuring instruments to measure these two terms. We can easily measure the mass of an object with the help of an ordinary balance. On the other hand, to measure the weight of an object, there requires spring balance.
Difference between their units
A standard for the measurement of an object is known as a unit. To measure the mass and weight of an object, we have to use two different units. The SI (System International) unit to measure the mass of an object is Kilogram and it is abbreviated as Kg. On the other hand, the SI (System International) unit to measure the weight of an object is Newton and it is abbreviated as N.
Difference between their formulas
In Physics, we can’t deny the importance of Mathematics because there require mathematical formulas to measure different terms. The formula to measure the mass of an object is given below;
F = ma                or             m = F/a
We can easily measure the mass of an object if we know the values of force and acceleration of this object. The formula to measure the weight of an object is also given below;
W = mg
We can easily measure the weight of an object if we know the values of mass and gravity of this object.
With the help of these formulas, it is also possible for us to convert the mass of an object into weight and vice versa. For example, if the mass of an object is 10Kg, we can convert it into weight in the following way;
W = 10*9.8 = 90.8N
External factors affecting mass and weight
As we know that mass is an intrinsic property of an object and that’s why there is no external factor that can affect the mass of an object. On the other hand, the weight of an object depends upon the mass of that object. Therefore, the force of attraction can easily influence the value of the weight of that object. That’s why if you are going to measure the quantity of an object, it is better for you to use mass rather than weight. Its reason is that the mass of an object remains the same at all the places, whereas, the weight of an object changes by changing the altitude.
Why we use mass in the formula to measure weight?
Most of the students think that due to lots of differences between mass and weight, why we are still using mass in the formula to measure weight. Its answer is that the weight of an object is due to the gravitational force that attracts a body. If the mass of an object is very small, the value of the gravitational force will also be small. That’s why we can observe that a fog particle remain suspended in the air. Due to this reason, it is necessary for us to use mass in the formula of the weight. Another reason is that mass is the functional property of the matter and weight is known as the consequence of that property.
To sum up, we can say that mass and weight depends on each other. Greater the value of the mass, greater will be its weight and vice versa. The main difference between two terms is that mass is a constant quantity, whereas, the weight of an object changes with the change in the altitude.
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## Why Is Milk White?

### What Is Milk?

No doubt, milk has become an important component of our diet. There are many benefits of milk. We can use milk to glow our skin, to strengthen our bones and teeth, to rebuild our muscles, to lose weight, and to lower the blood pressure. As we know that milk is a white liquid and it is produced by the mammary glands of the mammals. The milk is the primary source of nutrition for the newly born mammals because they are not able to digest the other kinds of food.

### Why Is The Colour Of Milk White?

When we see the colour of the milk, then it seems to us white. Now, a question comes to the mind that why is milk white rather than red, yellow, green or blue colour. As we know that the colour of a material depends on the properties of the material. Therefore, before going to know about the white colour of the milk, we should try to know the composition of the milk.

### The Composition Of The Milk

Generally, the milk is composed of carbohydrate, fat, protein, vitamins, minerals, and enzymes. When we talk about the gross composition of the milk, then we come to know that there is 87.7% water in the milk. Moreover, there is also 4.9% lactose and 3.4% fat in the milk. There are also minerals and proteins in the milk. The composition of minerals in the milk is 0.7% and the composition of proteins is 3.3% in the milk. As we know that we can get milk from a different species like cow, goat, sheep and buffaloes. The composition of the milk doesn’t remain constant for all the species. This composition of milk varies to some extent from one species to the other species. It is also interesting to know that this composition of the milk also depends upon the feed of the animals.

### What Is The Phenomenon Behind The White Colour Of The Milk?

As we know that the colour of a material depends on the properties of the material. This particular composition of the milk allows the milk to reflect all the visible wavelengths of light and there is no visible wavelength of the light is absorbed by the milk. The composition of all the visible wavelengths of the light provides us with the white colour of the milk.

### Why Is The Cow’s Milk Yellow?

As we have discussed earlier that the colour of a material depends upon the properties of the material. The composition of the cow’s milk is that the fat particles of the cow’s milk contain colouring pigment that is called the Beta-carotene. Whereas, the buffalo’s milk doesn’t contain this colouring pigment. Due to the presence of this colouring pigment, the composition of the cow’s milk is different from the composition of the buffalo’s milk. That’s why the buffalo’s milk is white and the cow’s milk is yellowish.

90% of the world’s milk needs are fulfilled with the help of the cow’s milk. First of all, the cow’s milk was drunk over 10,000 years ago in Afghanistan.