CBSE > Class 09 > Science | CBSE Board | Homework Help

Addiction is a complex condition, a brain disease that is manifested by compulsive substance use despite harmful consequence. People with addiction (severe substance use disorder) have an intense focus on using a certain substance(s), such as alcohol or drugs, to the point that it takes over their life.

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what are the differences between elements and compound?

Posted by Manikarnika Mishra 4 years, 11 months ago

CBSE > Class 09 > Science

2 answers

Gayatri Anne 4 years, 11 months ago

ELEMENT IS PURE SUBSTANCE AND IS MADE UP OF ONLY ONE TYPE OF ATOM. COMPOUND IS ALSO A PURE SUBSTANCE AND IS MADE UP OF MIXTURE OF ELEMENTS

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Bishal Paul 4 years, 11 months ago

The my policy this is a study on that I am a hopper you can explain the messages and I will do the 4

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What is Mitochondria.

Posted by Ritik Bisht 4 years, 11 months ago

CBSE > Class 09 > Science

4 answers

Bhumi Hingole 4 years, 10 months ago

Power house of cell

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Abhishek Kumar 4 years, 11 months ago

Mitochondria are the scavengers of cell

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Niyati Tyagi 4 years, 11 months ago

It's a power of the cell. It provides enedgy to the cell . It's a round tube like structure

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Yogita Ingle 4 years, 11 months ago

Mitochondria

Mitochondria are round "tube-like" organelles that provide energy to a cell in the form of ATP (Adenosine Triphosphate) for performing different chemical activities for the sustainance of life.
The mitochondria is also called powerhouse of the cell.
It is surrounded by two membranes.
The outer membrane is porous wherea the inner membrane has deep folds that provides a large surface to perform the chemical reactions required for the generation of ATP.
The inner membrane is compartmentalized into various cristae.
The ground substance or space enclosed by inner membrane is called matrix.
Mitochondria have their own DNA and ribosomes and are hence capable to produce some of their required proteins all by themselves.

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What is the total number of muscles in our body??

Posted by Palak Pandey 4 years, 11 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 4 years, 11 months ago

The muscular system is an organ system, involved majorly in the movement of the body. There are nearly 700 muscles that are connected to the bones of the skeletal system, which roughly half make up the human’s body weight. Every muscle is a different organ made of blood vessels, skeletal muscle tissue, nerves, and tendons. Muscle tissues are found in the heart, blood vessels, and digestive system.

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Which is the strongest bone in the body??

Posted by Palak Pandey 4 years, 11 months ago

CBSE > Class 09 > Science

4 answers

Prachi Sethi 4 years, 11 months ago

https://youtu.be/0pJVD5j6foA

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Ananya K 4 years, 11 months ago

The femur bone is the longest and strongest bone in the body.

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Niyati Tyagi 4 years, 11 months ago

Femur

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Yogita Ingle 4 years, 11 months ago

The femur is the bone in the human body which is strongest among all. It stretches the hip to the knee. It can withstand a force of as much as 1,800 to 2,500 pounds.

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A person walks along the side of a square field each side is 100m long. What is the maximum magnitude of displacement of the person in any time interval?

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

2 answers

Prachi Sethi 4 years, 11 months ago

https://youtu.be/0pJVD5j6foA

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Gaurav Seth 4 years, 11 months ago

The maximum displacement is the diagonal of the square field.

side of square = 100m
diagonal = √100² + 100² = √20000 = 100√2 m = 141.42m

So maximum displacement is 141.42m.

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A car moves 100m due east and then 25m due west a= what is the distance covered by the car. b= what is its displacement.

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

1 answers

Beyon P Binoy 4 years, 11 months ago

Distance covered by the car= 100+25 = 125m Displacement= 100-25 =75m

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A girl bends to touch her toes. Is the motions of her head an example of uniform motion or accelerate motion? Explain your answer.

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

3 answers

Ananya K 4 years, 11 months ago

The motion of the head of the girl while touching her toe is an example of accelerated motion because (i) The direction of her head is a circular path. So, The direction of velocity is always changing and so the velocity always changing.

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Akash And Prisha Yadav 4 years, 11 months ago

The motion of the head of the girl while touching her toe is an example of accelereted motion because (i) The direction of her head is a circular path. So, The direction of velocity is always changing and so the velocity always changing. (i.e - The velocity can never be constant). Since, the velocity is changing.

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Yogita Ingle 4 years, 11 months ago

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How can you get the distance travelled by an object from its speed time graph?

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

3 answers

Prachi Sethi 4 years, 11 months ago

https://youtu.be/0pJVD5j6foA

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Ananya K 4 years, 11 months ago

distance = rate x time. To solve for speed or rate use the formula for speed, s = d/t which means speed equals distance divided by time.

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Udita Singh 4 years, 11 months ago

By its slope

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How can you get the speed of an object from its distance time graph?

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

2 answers

Ananya K 4 years, 11 months ago

The speed of an object is calculated from a distance - time graph as the slope. The slope of a line represents how steep it is. In distance - time graphs, slope, which is the average speed is calculated by dividing a change in y value by the corresponding change in x-value.

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Yogita Ingle 4 years, 11 months ago

"Speed of an object can be determined from its distance-time graph using the following steps:

1. Identify the time interval and the corresponding distance interval on the curve.

2. Calculate the gradient for the said interval.

The gradient of the distance-time graph, that is, the slope of the said curve gives the speed of that object.

Say, for the time interval t₁ and t₂, the corresponding distance interval is s₁ and s₂ Then, the gradient (that is, speed) is given by "

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Give an example where the speed of an object first increase then remain constant for some time and then decrease.

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 4 years, 11 months ago

An example of the given situation is as follows-

A train/ metro that starts from rest gradually picks up speed and starts accelerating. At this stage, the speed increases but after sometime, the train acquires a constant speed( runs at a uniform speed). On approaching the next station, the train starts slowing down in order to halt( speed decreases).

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Distinguish between distance displacement a= an object moving along a straight answer line b= an object moving in a plane.

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

1 answers

Gaurav Seth 4 years, 11 months ago

distance is the actuall path covered by a body.
displacement is the shortest distance.
1. on a straight line distance is equal to displlacement but if the object come to its origin then displacement is 0.
2 on a moving plane distance is the path covered by body +path travelled by plane but the displacement is the distnace covered by plane only .

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What is difference between speed and velocity?

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

2 answers

Yogita Ingle 4 years, 11 months ago

No.	Differentiating Property	Velocity	Speed
1	Definition	Velocity can be defined as the rate at which an object changes position in a certain direction.	The rate at which an object covers a certain distance is known as speed.
2	Type of quantity	Vector quantity	Scalar quantity
3	Magnitude	Velocity can be zero, negative, or positive.	Speed can never be negative or zero.
4	Change of direction	The velocity of the object changes with the change in direction, therefore the object must follow one direction.	The average speed will continue to count even if the object changes direction.
5	Interrelation	An object may possess different velocities but the same speed.	Speed may or may not be equal to velocity.
6	Unit (SI)	Velocity is measured in m/s	Speed is measured in m/s

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Bhawna Dhami 4 years, 11 months ago

Speed =distance/time Velocity=displacement/time

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On what factors does acceleration due to gravity depend

Posted by Naitik Kumar 4 years, 11 months ago

CBSE > Class 09 > Science

1 answers

Aliza Taufiq 4 years, 11 months ago

distance and mass

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What is more accompanied by cooling? a) Evaporation b) Condensation Please answer

Posted by Aliza Taufiq 4 years, 11 months ago

CBSE > Class 09 > Science

2 answers

Niyati Tyagi 4 years, 11 months ago

Evaporation causes cooling

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Yogita Ingle 4 years, 11 months ago

Actually, evaporation is a cooling process because when liquid turns to gas, it needs more energy and so it has to take that energy from its surrounding. The energy is in the form of heat and when the energy (heat) leaves with the evaporating liquid; surrounding gets cooler.

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What is more accompanied by cooling? a) Evaporation b) Cooling

Posted by Aliza Taufiq 4 years, 11 months ago

CBSE > Class 09 > Science

3 answers

Prachi Sethi 4 years, 11 months ago

https://youtu.be/0pJVD5j6foA

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Sarita Panda 4 years, 11 months ago

Evaporation

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Aliza Taufiq 4 years, 11 months ago

a) Evaporation b) Condensation** Please answer.

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Difine average speed, uniform speed, uniform velocity and uniform acceleration?

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

1 answers

Keerti Singh 4 years, 11 months ago

Average speed = total distance covered/total time taken. Uniform speed: When object covers equal distance in equal intervals of time, this speed of the body is known as uniform speed. Uniform velocity: When velocity of object do not change with time, it is said to have uniform velocity. Uniform acceleration: Change of equal velocity in equal intervals of time is called uniform acceleration.

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Can the speed of a particle be negative? Can the velocity of a particle be negative? Give argument to support your answer.

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

1 answers

Lakshmi Thite 4 years, 11 months ago

No speed of a particle cannot be negative because it is a scalar quantity. Velocity can be positive negative and zero because it is a vector quantity

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A quantity is measured to be -30m/s. Is it speed or velocity? Give a reason for your answer.

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

1 answers

Aliza Taufiq 4 years, 11 months ago

I think It is speed because only magnitude is given here, not the direction which states that it is a scalar quantity (that is speed not velocity). Hope you get it...

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Give an example in which the distance traversed by a particle is larger than the magnitude of its displacement in the same.

Posted by Sweta Soreng 4 years, 11 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 4 years, 11 months ago

Distance travelled by a particale can be greater than the magnitude of displacement. For instance a person Jaibirjakhar goes from home to school which is 2 km from his home and returns back from the same path... The distance travelled will be 2+2=4 km while the displacement will be 0 km as the starting point and ending point is same.. hence distance in this case will be greater than the displacement at the same time..

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The boiling point of liquid argon is?

Posted by Sakshi Kumari 4 years, 11 months ago

CBSE > Class 09 > Science

2 answers

Yogita Ingle 4 years, 11 months ago

Liquid argon has a boiling point of –303°F (–186°C).

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Nisha Menon 4 years, 11 months ago

-185.8C

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Which is the smallest bone of our body

Posted by Heena Sheoran 4 years, 11 months ago

CBSE > Class 09 > Science

4 answers

Tejesh Sahu 4 years, 11 months ago

Stapes.

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Priyanshi Jadeja 4 years, 11 months ago

Stapes

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Yogita Ingle 4 years, 11 months ago

The smallest bone in the human body is called stapes, located in the middle ear.

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Sakshi Kumari 4 years, 11 months ago

Stapes. It is present in the middle ear

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Which is the longest bone in our body??and also hard???

Posted by Palak Pandey 4 years, 11 months ago

CBSE > Class 09 > Science

5 answers

Mehbub Ahmed 4 years, 11 months ago

It's femur or thigh bone

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Nisha Menon 4 years, 11 months ago

femur is the longest bone

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Priyanshi Jadeja 4 years, 11 months ago

Thigh bone

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Yogita Ingle 4 years, 11 months ago

The thigh bone (Femur) is almost 19.9 inches long and is the longest bone in the human body. It runes from the hip down to around the knee area.

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Foram Patel 4 years, 11 months ago

It's femur or thigh bone

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Why should we wear cotton clothes in summer

Posted by Daljit Rahad 4 years, 11 months ago

CBSE > Class 09 > Science

3 answers

Yogita Ingle 4 years, 11 months ago

We sweat more in the summer session. Cotton is a strong water absorber helps to absorb the sweat and introduce to the environment of evaporation. Our body takes out heat as the sweat evaporates from our body. Therefore our body loses heat and is cooled.

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Foram Patel 4 years, 11 months ago

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Mehbub Ahmed 4 years, 11 months ago

As cotton cloth are light and suck all the sweat of body and fell us cool.

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Define collenchyma, parenchyma and sclerenchyma

Posted by Ashirwad Chauhan 4 years, 11 months ago

CBSE > Class 09 > Science

2 answers

Yogita Ingle 4 years, 11 months ago

Simple tissues are of three types namely parenchyma, collenchyma and sclerenchyma.

Parenchyma – They are living cells and walled, soft in nature due to the presence of thin-walled cells
Collenchyma – These are characterized by uneven thick-walled living cells.
Sclerenchyma – They have cells with thickened lignified walls, providing them strength and making them waterproof.

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Foram Patel 4 years, 11 months ago

Parenchyma cells are the type of living plant cells, which are known for healing and repair mechanism, and food storage. ... Sclerenchyma cells are the matured dead cells and are found in wooden part or hard stem of the plant.

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Is ink a pure substance or a mixture

Posted by Anirudh Nautiyal 4 years, 11 months ago

CBSE > Class 09 > Science

3 answers

Priyanshi Jadeja 4 years, 11 months ago

Mixture

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Mehbub Ahmed 4 years, 11 months ago

Please give my answer.

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Mehbub Ahmed 4 years, 11 months ago

Ink is a mixture

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Liquid generally have lower density as compared to solid.

Posted by Sunil Yadav 4 years, 11 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 4 years, 9 months ago

Water can exist in three different physical states. Water does exist in the form of ice or snow in the solid-state. Water exists as water vapour or steam, in the gaseous state and it exists in the form of water in its liquid state.

The density of ice is less than water. Liquids generally have lower density as compared to solids but ice floats on water. When water freezes to form ice, some empty spaces are created. As a result, volume increases for the same mass of water.

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