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

As Work done= Force*Displacement And force=Mass*acceleration (ma) and Displacement ( distance or s)= 2as=v2-u2 s=v2-u2/2a Therefore, W=ma*v2-u2/2a a and a got cancelled (means from ma and 2a ,a gets cancelled) As object is starting from rest position u2=0 Therefore, m*v2/2 And take 2 as a whole and hence formula is derived, 1/2 mv2 You may also consult NCERT class 9 for better understanding !

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Which tissue in plants?

Posted by Sumit Verma 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Akanksha Kumari? 7 years, 2 months ago

Meristematic or permanent tissue is present in plants

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Calculate the work done by a student in lifting a 0.5 kg book from the ground and keeping it on a shelf of 1.5 m height

Posted by Thadala Vardhan Thadala Vardhan 7 years, 2 months ago

CBSE > Class 09 > Science

4 answers

Chaitanya Bhamare 7 years, 2 months ago

G=6.67x10raise to power -11 and g=9.8

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Akanksha Kumari? 7 years, 2 months ago

W= F×S = m × g × s = 0.5 × 10 × 1.5 = 7.5 J Thus the work done by the student is 7.5 J

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Shivam Yadav 7 years, 2 months ago

10 or 9.8

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Shivam Yadav 7 years, 2 months ago

What is the g value

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change 100 celcius into kelvin temperature..

Posted by Akash Omar 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Akanksha Kumari? 7 years, 2 months ago

Temp. On kelvin scale = temp. On Celsius scale + 273 Temp. On kelvin scale = 100 + 273 = 373

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Are the bodies moving with uniform acceleration ?

Posted by Anita Chopade 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Heet Lodha 7 years, 2 months ago

Yes the body moving in uniform acceleration but only some

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What are tears made of?

Posted by Saahil Khanna 7 years, 2 months ago

CBSE > Class 09 > Science

2 answers

Prathmesh Kadam 7 years, 2 months ago

Water and iodizedsalt

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Tanisi Agarwal 7 years, 2 months ago

Water and salt

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Derive the formula to calculate kinetic energy of an object according to 3 marks

Posted by Shivam Meena 7 years, 2 months ago

CBSE > Class 09 > Science

2 answers

Megha Bharti 7 years, 2 months ago

We know that work=F.s =ma s (=v2- u2/2a) so ma×v2- u2/2a then 1/2 m (v2- u2) (u=0) then k.e = 1/2mv2

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Akanksha Kumari? 7 years, 2 months ago

W= m × a × s = m × a × v2- u2/2a = 1/2 m (v2 -u2) Consider u= 0 then W= 1/2 mv2 Hence the kinetic energy possessed by an object of mass m moving with velocity v is : K.E = 1/2mv2

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What is slinky

Posted by Shubhra Agarwal 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Rajesh Kumar 7 years, 2 months ago

Fitting closely to the line of the body

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Make a flow chart of animal tissue.

Posted by Prashant Bhati 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Gaurav Seth 7 years, 2 months ago

Flow chart of all animal tissues individual.

Hope this ll help you.

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How to fimd mole concept

Posted by Praneet Shrimal Shrimal 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Ritik Tevathiya 7 years, 2 months ago

Mole concept is a link between gram atomic mass and 6.022x10power24

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Calculate the mass of one molecule of nitrogen gas

Posted by Ashutosh Atray 7 years, 2 months ago

CBSE > Class 09 > Science

2 answers

Ritik Tevathiya 7 years, 2 months ago

Gram atomic mass of nitrogen is 14g N^2 is 14x2=28

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Kumkum Sarswat 7 years, 2 months ago

One molecule of nitrogen gas means N2 = atomic mass of nitrogen x 2 = 14 x 2 =28 u Hope it will help you ??????????

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what is the symbol of hydrogen..?

Posted by Sangita Nayak 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 6 years, 1 month ago

H is the symbol of hydrogen

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What do you mean by octet?

Posted by Vedanshi Singh 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Khushi Boora 7 years, 2 months ago

Group of eight valence electrons in an atom.

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What is funa??

Posted by Debendu Maity 7 years, 2 months ago

CBSE > Class 09 > Science

4 answers

Prashant Bhati 7 years, 2 months ago

a)The species of animal are refered as fauna. b)India is rich in fauna. It is approximately 90,000 of animal species. c)The country has more than 1200 species of birds and 2,500 species of fish. d)Animals are dependent on flora and other animals for food.

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Kumkum Sarswat 7 years, 2 months ago

Species of plants in a particular region ??????

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Jiya Kumari 7 years, 2 months ago

It's not funa it's fauna Fauna is a species of plants in a particular region. I hope my answer is sutable to understand you

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Sayahnika Mishra 7 years, 2 months ago

Do you mean fauna

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Why antibiotics are not able to kill viruses?

Posted by Sanya Shourya 7 years, 2 months ago

CBSE > Class 09 > Science

2 answers

Jaishree Sanodiya 7 years, 2 months ago

Because the pathway of virus is different from bacteria.Bacteria make cyst for their life cycle but virus doesn't make cyst for their life cycle.They use our machinery for their life cycle

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Sayahnika Mishra 7 years, 2 months ago

Virus multiply in the host cells and lives on the border line of living and non-living.

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Why light is called electromagnetic waves?

Posted by Sanya Shourya 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Prashant Bhati 7 years, 2 months ago

There are waves of energy and light moving all around us in the form of tv and audio transmissions, gamma radiation from space,and heat in the atmosphere .Scientists call them all eletromagnatic radiation. The waves of energy are called electromagnetic (EM) because they have oscillating electric and magnetic feilds.

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Explain the experiment of rutherford with alpha particle and draw its diagram

Posted by Chaitanya Bhamare 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 6 years, 1 month ago

Rutherford postulated that the atom must contain large empty spaces as most of the α-particles passed through it without getting deflected. Some α-particles were deflected by the foil through small angles, while some were deflected through very large angles. Thus, Rutherford concluded that the positively charged particles in an atom must be concentrated in a very small space.

One out of every 12,000 particles were deflected through 180o showing a full rebound. Thus, Rutherford came to the conclusion that all the positive charges of the atom and most of the mass of the atom is concentrated in a very small volume within the atom.

Rutherford named this small space inside the atom as the nucleus of the atom or the atomic nucleus. On the basis of these observations, Rutherford calculated that the atomic nucleus is 10⁵ times smaller than the total area of the atom. The radius of the atom is 10^-8 centimetres while the radius of the nucleus is 10^-13 centimetres.

Thus, we can say that the atom is relatively hollow with a heavy nucleus at its centre. The electrons arranged around the nucleus possess negligible mass.

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What is electrodes?

Posted by Shivam Tiwari 7 years, 2 months ago

CBSE > Class 09 > Science

1 answers

Khushi Boora 7 years, 2 months ago

Good conductor that is joined at positive or negative terminal of battery.

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What are wavelength ,frequency , time period and amplitude of sound wave?

Posted by Tinku Kamboj 7 years, 2 months ago

CBSE > Class 09 > Science

2 answers

Archna Toppo 7 years, 2 months ago

Wavelength :-The distance between two succesive crust or trough is called wavelength . Ferquency:- Number of vibration in one second is called frequency . Time period :- Time taken to complete one oscillation is called time period. Amplitute :- The maximum displacement of partical is called amplitute.

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Tinku Kamboj 5 years, 11 months ago

Answer

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Find the ratio of gravity earth to moon

Posted by Anjali Khool 7 years, 2 months ago

CBSE > Class 09 > Science