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

Now try to break the chalk you can easily break it but it is more difficult to break a brick because the interparticle attraction of particles of brick is more than that of the chalk

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Ziyesha Sourav 7 years, 1 month ago

Take a piece of chalk and a brick

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Name two singled cell organisms

Posted by Mangala Manu 7 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Akanksha Kumari? 7 years, 1 month ago

Amoeba and paramecium

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How can a saturated solution can be changed into unsaturated solution?.... please answer my question.... please.. please.. please.. please

Posted by Simran Das 7 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Nandini Sharma❤️ 7 years, 1 month ago

We can add more solvent to it or we can heat it

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How do reptiles differ from amphibians

Posted by Samoju Dheep Chandu 7 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Nandini Sharma❤️ 7 years, 1 month ago

1. Amphibians have mucus glands present on their skin whereas the skin of reptiles is covered with scale. 2. Amphibians lay their eggs in both water and land whereas reptiles do not need to lay their eggs in water.

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What is D.D.T.

Posted by Sheetal Stark 7 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Sayahnika Mishra 7 years, 1 month ago

It is a type of pesticides

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What is the amplitude

Posted by Manishwar Sri 7 years, 1 month ago

CBSE > Class 09 > Science

5 answers

Atul Kuwar 7 years, 1 month ago

Maximum displacement from its mean position is called amplitude

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Harshit Pandey 7 years, 1 month ago

The maximum distance between the medium and crest or trough Hope its help you

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Akanksha Kumari? 7 years, 1 month ago

The maximum displacement of a body from its original position is called its amplitude.

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Rishav Raj 7 years, 1 month ago

The maximum distance between mean position and extreme position

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Ankit Singh 7 years, 1 month ago

The distance between the crust from zero line distrabance

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Explain Newton 3 law of motion with example?

Posted by Nemikham Nemikham 7 years, 1 month ago

CBSE > Class 09 > Science

3 answers

Vandana Sharma 7 years, 1 month ago

Third low of motion: To every action there is an equal and opposite reaction and they act on two different bodies. Example,when air rushes out of a balloon,the opposite reaction is that the balloon flies up.

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Harshit Pandey 7 years, 1 month ago

It states that every action has an equal and opposite reaction

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Paras Khurana 7 years, 1 month ago

It states that Every action has equal and opposite reaction . For example :- when a sailor jumps from a boat. As the sailor jumps forward, the boat moves backward

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Application questions

Posted by Aswathy Baiju 7 years, 1 month ago

CBSE > Class 09 > Science

0 answers

ANSWER

Symbol of amplitude

Posted by Syed Anas 7 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 7 years, 1 month ago

Normally the symbol A is used to represent the amplitude of a wave. The SI unit of amplitude is the metre (m). The amplitude of a wave is the maximum disturbance or displacement of the medium from the equilibrium (rest) position.

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Proof that ke=1/2 mv2

Posted by Ayush Ffcs Tgh 7 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Nickson S 7 years, 1 month ago

W=fs But w.k.t f=ma and s=v2-u2/2a =>w=ma*v2-u2/2a =>w=1/2m(v2-u2) Since u=o W=1/2 mv2 Therefore ke=1/2 mv2 Hence proved.

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Harshit Pandey 7 years, 1 month ago

As s=v2-u2/2a.(from third eq. Of motion) As f=ma(from 2 law of force) W=fs W=ma×v2-u2/2a W=m×v2-u2/2 If the object starts from rest than u=0 then, E.k=1/2mv2 Hope it is help u

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What are genital papillae in earthworm?

Posted by Aditi D 7 years, 1 month ago

CBSE > Class 09 > Science

0 answers

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How salt is a solid

Posted by Annapurna Anand 7 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Garima Chauhan 7 years, 1 month ago

compound with this kind of electrostatic attraction called lonic bonds,are almost alway solid at room temperat

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Valency of cl ion

Posted by Black Shark 7 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Akanksha Kumari? 7 years, 1 month ago

Cl (-1)

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Vallency of cl ion

Posted by Black Shark 7 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Ronit Rana 7 years, 1 month ago

Since one Cl atom gains 1e to achieve the inert gas electron configuration, so the electovalency of Cl is1-

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Akanksha Kumari? 7 years, 1 month ago

Because it accepts 1 electron

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Why is matter particulate?

Posted by Bhavika Chandrawat 7 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 7 years, 1 month ago

Matter is defined as that which has mass and occupies space. It is indeed made of particles.
Space is that which is occupied by matter. So, any definition of space exists only if there is matter.
All matter is particulate in nature. This means there are spaces which has no matter between the bits of matter. This is called the atomic nature of matter."

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What is the effect of increase in temperature on the solid state of matter?

Posted by Saumya Shukla 7 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Anchal Bharti? 7 years, 1 month ago

It maybe sublimate

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Yogita Ingle 7 years, 1 month ago

Temperature has a direct effect on whether a substance exists as a solid, liquid or gas. Generally, increasing the temperature turns solids into liquids and liquids into gases; reducing it turns gases into liquids and liquids into solids.
The particles break kinetic energy and expand. Increase in temperature also increases solublity.

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Explain second Law of motion.....

Posted by Sandhya Singh 7 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Harshit Pandey 7 years, 1 month ago

It state that the rate of change of momentum is directly proportional to the applied unbalanced force

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Vivansh Pandey 7 years, 1 month ago

Newton's second law of motion pertains to the behavior of objects for which all existing forces are not balanced. The second law states that the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object. The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object. As the force acting upon an object is increased, the acceleration of the object is increased. As the mass of an object is increased, the acceleration of the object is decreased.

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Conservation of mass practicle

Posted by Sheela Sharma 7 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 7 years, 1 month ago

Laws of conservation of mass

The law states that mass can neither be created nor destroyed in a chemical reaction i.e. Total masses of reactants is equal to the sum of masses of products and the masses of unreacted reactants. For instance, the reaction of carbon with oxygen to produce carbon-dioxide involves conservation of mass in the following way.

C (12g) + O₂ (32g) = CO₂ (44g)

Here we used 12 g of carbon and 32 g of oxygen. After reaction the amount of carbon –dioxide produced will be 44g i.e. the sum total of the amount of carbon and oxygen used.

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Motion equation 3

Posted by Shoaib Alvi 7 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Sharad Sharma 7 years, 1 month ago

V^2 =u^2 +2as v= final velocity. U= Inital velocity. A= acceleration. S= distance

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Poorvi Jain 7 years, 1 month ago

V^2-- u^2=2as

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How can we make an unsaturated solution into saturated solution? Please answer my question please please please please.....

Posted by Simran Das 7 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Poorvi Jain 7 years, 1 month ago

A saturated solution is that which is dissolved as much solute as it is capable of dissolving. By heating the solution a saturated solution can be changed into an unsaturated solution. Without adding any solvent it can be changed into an unsaturated solution. Example: on heating a saturated solution of sugar in high temperature, it starts dissolving.

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Yogita Ingle 7 years, 1 month ago

A solution is a homogeneous mixture of two or more substances.
Component of the solution : A solution has two components. The component of a solution that is present in larger quantity is called the solvent and the component present in smaller quantity is called as solute.
Solvent +Solute = Solution
Example: Tincture Iodine. In tincture of iodine, the iodine is the solute and alcohol is the solvent.
Types of Solutions based on Concentration:
Saturated solution: A solution which will not dissolve anymore solute is called a saturated solution.
Unsaturated solution : A solution in which more of the solute will dissolve is called an unsaturated solution.
Thus in order to convert a saturated solution into an un-saturated solution is by dilution process.
On dilution the concentration of solution decreases thus it requires more salt to be added to it to make it as saturated solution.

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State SI unit of kinetic energy

Posted by Farhaan Fahi 7 years, 1 month ago

CBSE > Class 09 > Science

4 answers

Akanksha Kumari? 7 years, 1 month ago

SI unit of allowing the types of energy is Joule

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D K 7 years, 1 month ago

Joules(J)

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Poorvi Jain 7 years, 1 month ago

Joules

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Madhukar Dhurve 7 years, 1 month ago

joules

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How can we make an unsaturated solution into saturated solution?

Posted by Simran Das 7 years, 1 month ago

CBSE > Class 09 > Science

2 answers

D K 7 years, 1 month ago

We can make an unsaturayed solution into a saturated solution by adding the amount of solute a solvent can have such that no more solute can be added or dissolved

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Poorvi Jain 7 years, 1 month ago

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How can we make an unsaturated solution into saturated solution? Give me three ways of it.

Posted by Simran Das 7 years, 1 month ago

CBSE > Class 09 > Science

0 answers

ANSWER

Dispersed phase and dispersion medium

Posted by Aditya Pandey 7 years, 1 month ago

CBSE > Class 09 > Science

3 answers

Poorvi Jain 7 years, 1 month ago

DISPERSED PHASE The component which is less in amount is known as dispersed phase. It is solute like component . It is used for colloidal solutions. DISPERSION MEDIUM The component in which dispersed phase is suspended is known as dispersing medium. It is also used for colloidal solutions. Let us take the example of a colloid named foam. In foam, dispersed phase is gas while dispersion medium is liquid. The examples of foam are shaving cream etc.

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Simran Das 7 years, 1 month ago

Dispersed phase is a type of a solute which we commonly mixed in a solvent. Dispersion medium is a type of medium in which we commonly mix a solute. For example.... dispersion phase.....salt and dispersion medium...... water.

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Sushma Nirankari 7 years, 1 month ago

Dispersed phase is in small amount and dispersion medium is in large amount

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The force of7 N acts on an object .the displacement is say 8m.in the direction of the force .let us take it that the force act on the object through the displacement.what os the work done in this case..explain.?

Posted by Neya Saji 7 years, 1 month ago

CBSE > Class 09 > Science

3 answers

D K 7 years, 1 month ago

Force=7N Displacement=8m Work done= Force × Displacement Work done=7×8 Work done=56J Explanation: we know that work is done when a body displaces its mean position or shows displacement on applying force.. We have taken the force as positive because it is given in the question that the displacement took place in the direction of the force applied

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Poorvi Jain 7 years, 1 month ago

Use W=fscostheta

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Aditya Pandey 7 years, 1 month ago

In this case the force done by an object , object moves opposite to the direction force that applied on it

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derive the eqation of law of conservation of energy

Posted by Aashish Raj 7 years, 1 month ago

CBSE > Class 09 > Science

4 answers

Nandini Sharma❤️ 7 years, 1 month ago

Law of conservation of energy states that energy can neither be created nor it can be destroyed but it can be converted from one type to another type.

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Poorvi Jain 7 years, 1 month ago

Proof for Law of Conservation of Energy: Considering the potential energy at the surface of the earth to be zero. Let us see an example of a fruit falling from a tree. Consider a point A, which is at some height ‘H’ from the ground on the tree, the velocity of the fruit is zero hence potential energy is maximum there. E = mgH ———- (1) When the fruit is falling, its potential energy is decreasing and kinetic energy is increasing. At point B, which is near the bottom of the tree, the fruit is falling freely under gravity and is at a height X from the ground, and it has a speed as it reaches point B. So, at this point it will have both kinetic and potential energy. E = K.E + P.E P.E = mgX ——— (2) According to third equation of motion, v2=2g(H–X)⇒12mv2=12m.2g(H–X)⇒K.E=12m.2g(H–X)⇒K.E=mg(H–X) K.E=mg(H-X)——– (3) Using (1), (2) and (3) E = mg(H – X) + mgX E = mg(H – X + X) E = mgH Similarly, if we see the energy at point C which is at the bottom of the tree, it will come out to be mgH. K.E = P.E => P.E = K.E = E2 ——– (4) E2 is the new energy Where, E = mgH2 H2 is the new height. As the body is at height X from the ground, P.E = mgX ——— (5) Using (4) and (5) we get, mgX=mgH2⇒X=H2 H2 is referred to the new height

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Gaurav Seth 7 years, 1 month ago

Proof for Law of Conservation of Energy:

Considering the potential energy at the surface of the earth to be zero. Let us see an example of a fruit falling from a tree.

Consider a point A, which is at some height ‘H’ from the ground on the tree, the velocity of the fruit is zero hence potential energy is maximum there.

E = mgH ———- (1)

When the fruit is falling, its potential energy is decreasing and kinetic energy is increasing.

At point B, which is near the bottom of the tree, the fruit is falling freely under gravity and is at a height X from the ground, and it has a speed as it reaches point B. So, at this point it will have both kinetic and potential energy.

E = K.E + P.E

P.E = mgX ——— (2)

According to third equation of motion,

v2=2g(H–X)⇒12mv2=12m.2g(H–X)⇒K.E=12m.2g(H–X)⇒K.E=mg(H–X)

K.E=mg(H-X)——– (3)

Using (1), (2) and (3)

E = mg(H – X) + mgX

E = mg(H – X + X)

E = mgH

Similarly, if we see the energy at point C which is at the bottom of the tree, it will come out to be mgH. We can see as the fruit is falling to the bottom and here, potential energy is getting converted into kinetic energy. So there must be a point where kinetic energy becomes equal to potential energy. Suppose we need to find that height ‘x’ from the ground. We know that at that point,

K.E = P.E

=> P.E = K.E = E2 ——– (4)

E2 is the new energy

Where, E = mgH2

H2 is the new height.

As the body is at height X from the ground,

P.E = mgX ——— (5)

Using (4) and (5) we get,

mgX=mgH2⇒X=H2

H2 is referred to the new height

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Shalu Kumari 7 years, 1 month ago

It neither be created nore be destroied. It convert into another type of energy

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ANSWER

derive the eqation of conservation of linear momentum

Posted by Aashish Raj 7 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Gaurav Seth 7 years, 1 month ago

Law of conservation of momentum states that when two objects collide with each other , the sum of their linear momentum always remains same or we can say conserved and is not effected by any action, reaction only in case is no external unbalanced force is applied on the bodies.

DERIVING THE LAW OF CONSERVATION OF MOMENTUM-

Let,

mA = Mass of ball A
mB= Mass of ball Ba

uA= initial velocity of ball A
uB= initial velocity of ball B

vA= Velocity after collision of ball A
vB= Velocity after collision of ball B

Fab= Force exerted by A on B
Fba= Force exerted by B on A

Now,

Change in momentum of A= momentum of A after collision - momentum of A before collision

= mA vA - mA uA

Rate of change of momentum A= Change in momentum of A/ time taken

= mA vA - mA uA/t

Force exerted by B on A (Fba)=

Fba= mA vA - mA uA/t. [i]

In the same way,

Rate of change of momentum of B=

mV vB - mB uB/t

Force exerted by A on B (Fab)=

Fab= mB vB - mB uB/t. [ii]

Newton's third law of motion states that every action has an equal and opposite reaction, then,

Fab= -Fba [ ' -- ' sign is used to indicate that 1 object is moving in opposite direction after collision]

Using [i] and [ii] , we have

mB vB - mB uB/t = - (mA vA - mA uA/t)

mB vB - mB uB= - mA vA + mA uA

Finally we get,

mB vB + mA vA = mB uB + mA uA

This is the derivation of conservation of linear momentum.

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what is the diffeence between osmosis and diffusion

Posted by Sangita???? Ankita 7 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Gaurav Seth 7 years, 1 month ago

<th>BASIS FOR COMPARISON</th> <th>OSMOSIS</th> <th>DIFFUSION</th>

Meaning	The movement of liquid (solvent) especially water from the higher region concentration to the region of lower concentration, through the semipermeable membrane is called osmosis.	The movement of molecules (solid, liquid or gases) from a region of higher concentration to the lower region concentration, but not necessarily through a semi-permeable membrane is called diffusion.
Semi-permeable membrane	The motion is through the semi-permeable membrane.	The motion is direct and does not require the semi-permeable membrane.
Medium	This process undertakes in the liquid medium.	This process undertakes in any medium (solid, liquid and gases).
Type of diffusing molecule	The movement is basically of solvent (water).	The movement can be in solid, liquid, or gases.
Rate of process	Osmosis is a slow process.	Diffusion is the fast process.
Free-energy	Osmosis is dependent on one solvent to the another for the reduction of free energy.	It is the movement of molecules from the area of their higher free energy to the area of the lower free energy.
Importance	1. Osmosis is important in animals for maintaining the water at the cellular level, also in transporting the nutrients, cell-cell diffusion. 2. In plants, it is helpful in maintaining the turgidity, provides mechanical support, prevents excess water loss, and responsible for absorption of water from the soil.	Diffusion is important in animals at the time of creating energy, during respiration it helps in exchange of gases, while in plants it is also helpful in the process of transpiration and photosynthesis.

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Naman Dhandharia 7 years, 1 month ago

1.Osmosis is the process in which only water molecules move from higher higher conc. to lower but in diffusion any substance except water molecules moves from higher conc. to lower

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