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

When a satellite moves around the Earth in a circular path, then the force of gravity acts on it directed towards the centre. The motion of the satellite is in the horizontal plane. Therefore, the force of gravity of Earth on the satellite and the direction of motion of satellite are perpendicular to each other. Therefore, net work done = Fs cos 900 = 0. That is, the work done by the force of gravity on a satellite moving around the Earth is zero.

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Vaibhav Verma 3 years ago

Work done would be 0 Since, satellite orbits earths in a circular path and from every point earth's radius to satellite is always perpendicular. Also, Since, work done Perpendicularly = Fd cos theeta. (Ø)Where cos theeta (ø) =90°= 0 Henceforth work done = 0 J

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ANSWER

What is the frequency of sound of wavelength 50cm?

Posted by Lakshita Arora 3 years, 1 month ago

CBSE > Class 09 > Science

3 answers

Swati Yadav 3 years, 1 month ago

Lambda 50 cm and frequency 5kHz

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Anand Chaudhary 3 years, 1 month ago

Show the times of animal tissue using flow chart

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Rajkumari Patidar 3 years, 1 month ago

A sound wave has frequency of 5kHz and wavelength 50 cm.

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ANSWER

What is sound and how it is produced?

Posted by Sarthak Mittal 3 years, 1 month ago

CBSE > Class 09 > Science

3 answers

Dipti Suryawanshi 3 years, 1 month ago

Sound is a form of energy which creates distubance. Sound is produced and propogated through vibrations. Vibration plays a important role in propogation and production of sound

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Daksh Gupta 3 years, 1 month ago

Sound is a form of energy which produces sensation of hearing in our ears. Sound is produced through vibrations caused by vibrating objects

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Om Tulsyan 3 years, 1 month ago

It is a type of energy which produces when an object vibrates.

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ANSWER

Mahesh moving on a road with a uniform acceleration covers 20 m/s in one second and 40 m in 2 second . what is the acceleration?

Posted by Abhijeet Sharma 3 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Preeti Dabral 3 years, 1 month ago

distance travelled in 1st second=20m

time taken to travel this distance=1s

So speed in first second is dist/time = 20m/s

Similarly speed in 2nd second is 40m/s

Now acceleration = dv/dt

Here dv means change in v, where v is velocity and dt means change in t where t is time interval.

Change in velocity = final vel. — initial vel.

That is, 40-20 = 20m/s

And change in time = 2 — 1 = 1s

So acceleration is 20m/s / 1s = 20m/s^2 Ans.

Metre per second square is the standard unit of acceleration.

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ANSWER

Why are cells called structural and basic unit of life ?

Posted by Nishit Agarwal 3 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Preeti Dabral 3 years, 1 month ago

Living cells have certain specific components within it known as cell organelles. Each kind of cell organelle performs a specific function, such as making new materials in the cells, release of waste, transportation, etc. Thus, a cell can perform all its functions with the help of these organelles. That is why the cells are called structural and functional unit of life.

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How endoplasmic reticullam and golgi body are interconnected to each other?

Posted by Nimish Srivastava 3 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Preeti Dabral 3 years, 1 month ago

A protein called coat protein II (COPII; green) forms vesicles that transport from the endoplasmic reticulum (ER) to the Golgi. A different protein called coat protein I (COPI; red) forms vesicles for transport in the other direction, from the Golgi to the ER. COPI also forms vesicles for intra-Golgi transport.

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Prince Panday 3 years, 1 month ago

Hii

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ANSWER

Can we make viruses from DNA 🧬. HOW?

Posted by Shakur Ansari 3 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Preeti Dabral 3 years, 1 month ago

The virulent nucleic acid sequence hijacks the cellular machinery to self-replicate, lyse the cell, spread, and infect other cells. Using reverse genetics, the sequence of a viral genome can be identified, including that of its different strains and variants.

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ANSWER

Write formula for average power

Posted by Roddy Wrangler 3 years, 1 month ago

CBSE > Class 09 > Science

5 answers

Smriti Gupta 3 years, 1 month ago

W/t

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Shreya Shandilya 3 years, 1 month ago

Total work done /total time taken

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Kahan Kalsariya 3 years, 1 month ago

W/t

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R.Preety Ramaesh 3 years, 1 month ago

W/t

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Prarthana Sajayan 3 years, 1 month ago

Average power = w/t

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ANSWER

What are macronutrients and why are they called macronutrients

Posted by Bitu Kumar 3 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Nimish Srivastava 3 years, 1 month ago

The nutrients which are needed by the plants in more quantity are known as macronutrients. The plant get these nutrients from soil.

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Prarthana Sajayan 3 years, 1 month ago

Some of the nutrients for plants are required in large quantity called the macro-nutrients.As by it's meaning macro means large therefore it is called macro-nutrients.

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ANSWER

What is the main function of mitochondria

Posted by K. Tushar 3 years, 1 month ago

CBSE > Class 09 > Science

5 answers

Nimish Srivastava 3 years, 1 month ago

The mitochondria is generally known as the power house of the cell. It is a semi-autonomous organelle which have their own DNA and ribosomes therefore it can synthesize some proteins on their own. It synthesize ATP(Adinoscene triphisphate) which is also known as the energy currency of the cell. It is a double membrane bound cell oraganelle in which external membrane is porous and the internal membrane is deeply folded which increase the surface for ATP production.

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Shreya Rai 3 years, 1 month ago

They are semi- autonomous organelle they divide themself. They are double membrane. Have their own DNA. They produce energy using cellular respiration

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Kahan Kalsariya 3 years, 1 month ago

This power house of the cell

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Harsh Kumar 3 years, 1 month ago

To produce energy

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Aryan Patoliya 3 years, 1 month ago

2 equation of motion

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ANSWER

A 0.24g sample of compound of oxygen and boron was found by anallysis to contain 0.096g of boron and 0.144 g of oxygen. Calculate the percentage composition of the compound by weight

Posted by Hasya Savaya 3 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Manoj Lohia 3 years, 1 month ago

Sample of compound= 0.24 gram Sample of Boron =0.096 g Sample of oxygen =0.144 gram Percentage of Boron =0.096/ 0.24* 100 = 40% Percentage of oxygen= 0.144/ 0.24* 100 = 60%

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K. Tushar 3 years, 1 month ago

No no

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ANSWER

How was neutron discovered ?

Posted by Jasnoor Saini 3 years, 1 month ago

CBSE > Class 09 > Science

5 answers

Shreya Shandilya 3 years, 1 month ago

James Chedwik was discovered it but How it is writeen on his exp.

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Kahan Kalsariya 3 years, 1 month ago

James chedwick

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Raunak Yadav 3 years, 1 month ago

James Chadwik

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Kunal Rajput 3 years, 1 month ago

J chadwick

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Meenakshi Dasila 3 years, 1 month ago

J.chandwik

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ANSWER

If the displacement of an object is proportional to square of time then the object moves with

Posted by Chitralekha Bhati 3 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Barsha Deb 3 years, 1 month ago

Uniformly accelerated motion

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ANSWER

Reflection of sound

Posted by Anand Chaudhary 3 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Devika Prajapati 3 years ago

The bouncing back of the sound when it strike with a hard surface is called reflection of the sound

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Arshpreet Kaur 3 years, 1 month ago

Answer :– Reflection is a phenomenon of reversion of a wave going from one medium to the same medium after striking the second medium. Sound wave also experience reflection like other waves.

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ANSWER

Mass of proton is ________ times the mass of an electron

Posted by Neha Srinitya Banoth 3 years, 1 month ago

CBSE > Class 09 > Science

5 answers

Preeti Dabral 3 years, 1 month ago

1836

2Thank You

Smriti Gupta 3 years, 1 month ago

1840

0Thank You

Nimish Srivastava 3 years, 1 month ago

2000 times

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Roshni Roshni 3 years, 1 month ago

2000

1Thank You

Prerna Pawar 3 years, 1 month ago

1836

1Thank You

ANSWER

What ix homogeneous

Posted by Anshika Yadav 3 years, 1 month ago

CBSE > Class 09 > Science

5 answers

Raunak Yadav 3 years, 1 month ago

Hio

1Thank You

Kunal Rajput 3 years, 1 month ago

When two substance are uniformly mix

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Roshni Roshni 3 years, 1 month ago

When two or more component that just mix together uniformly without any separation boundary with call homogeneus mixture

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Shivam Gupta 3 years, 1 month ago

In this type of mixture properties are the same in every portion. Example - cement , milk, e.t.c

2Thank You

Shivam Gupta 3 years, 1 month ago

3Thank You

ANSWER

List out the postulates of Thomson atomic model

Posted by Sarnika .M 3 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Barsha Deb 3 years, 1 month ago

According to the postulates of Thomson's atomic model, an atom resembles a sphere of positive charge with electrons (negatively charged particles) present inside the sphere. The positive and negative charge is equal in magnitude and therefore an atom has no charge as a whole and is electrically neutral.

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ANSWER

Exam me important questions konse hoge

Posted by Mahi Tauk 3 years, 1 month ago

CBSE > Class 09 > Science

3 answers

Shreya Shandilya 3 years, 1 month ago

Question mujhe pata aap khud pe confidence rakhiye

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Kunal Rajput 3 years, 1 month ago

Land bta ve

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Jassika Goel 3 years, 1 month ago

Hamko kya pta

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ANSWER

What type of project we can make on food security?

Posted by Pushpanjali 😗 3 years, 1 month ago

CBSE > Class 09 > Science

1 answers

Ravinder Singh 3 years, 1 month ago

Ration shops

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ANSWER

Define pure and impure substances

Posted by Sandeep Yadav 3 years, 1 month ago

CBSE > Class 09 > Science

4 answers

Piyush Singh 3 years, 1 month ago

Pure substance is the made up of only one kind of particles

3Thank You

Saurabh Yadav 3 years, 1 month ago

Mixture is a kind of substance in which two or more than different kind of atom or particle present in it

3Thank You

Saurabh Yadav 3 years, 1 month ago

Impure substance means mixtures

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Saurabh Yadav 3 years, 1 month ago

Pure substance is a kind of substance in which only one kind of particles present in it

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What is Biological components,?

Posted by Vidhi Maan 3 years, 1 month ago

CBSE > Class 09 > Science

2 answers

Preeti Dabral 3 years, 1 month ago

The biological component includes the plants, animals, insects, earthworms, nematodes, arthropods, protozoa, fungi, and bacteria that live in the soil. The biological community is a very important component of soil health

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Raunak Yadav 3 years, 1 month ago

The biological component are animals,plants,bacteria,insects,fungi,porifera,cnideria,platyhelmenithes,ctenophora,coelentrata,nematoda,arthropoda,mollusca,

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