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Showing posts from October, 2015

### Newton's Second Law of Motion For Class 9

Newton's Second law of motion: It states that rate of change of momentum is directly proportional to unbalance external force. And change of momentum is in the direction of unbalance force.
Mathematical Derivation: Initial momentum , Pi = mu
Final momentum , Pf = mv
Change in momentum ,&#x2206p = Pf - Pi
= mv - mu
But we know that rate of change of momentum is directly proportional to the applied unbalanced force.
∴ F &#x221D &#x2206p/t
or F &#x221D (mv - mu ) / t/
Or F &#x221D m. ( v -u )/t
Or F &#x221D m. a , Where a= Acceleration
Or F = k. m. a ,
Or F = 1. m. a , In SI system K=1
∴ F = m. a

### Newton's First Law of Motion Class 9 | Law of Inertia

Newton's First Laws of Motion { Law of Inertia }- It states that a body continue in its state of rest or of uniform motion until it is comepelled by any external unbalance forces. This laws is also known as law of inertia.Inertia is the proerty of a body which cause it to maintain its state of motion or rest.Unbalanced Forces : When two unequal forces acts on an object and the object change its state then we say that the forces are unbalance.
Unbalance forces can be understood from example of tug of war.
Watch this video.

### List of Hindi Difficult Words

Learning Hindi is easy if we are going in right way. Many of us are struggling for Hindi learning. We already have created Youtube videos for learning hindi . However We need practice to write correctly. This is the list of Hindi words in which a student of class 5 have created mistakes are. This is a tested list of words. I think many students do mistakes while writing these Hindi words. I suggest you to practice these words and post your mistakes if possible. There are Videos at the end for learning Hindi
उचित
पछताएगा
न्याय
गिर
बकरी
पेचिश
पीलिया
त्वचा
योग्य
मानव
इकाई
व्यवस्थित
वर्णमाला
उच्चारण
व्यवस्थापना
उच्चारित
इकाईयां
तुम्हारे
विवाह
धृष्टता
दूँगी
पक्षी
विशेष
समाज
ब्राह्मण
पहरा
कार्य
प्राप्त
खरीद

शीतल
जादू
स्वच्छ
वायु
बीमारी
पढ़ने
अकाल
समस्याए
प्रयोग
अविष्कार
देवदार
रसायनों
आत्मकथा
परिशान
बचाया
चंगुल
कूदना
भावना
सहभागिता
पढ़ाई
निगरानी
चिंता
मौखिक
संस्कृत
इसलिए
देवनागरी
लिपि
उचित
विमाला
ओतिकड़म
चमत्कार
उपाय
सरोवर

### In triangle ABC, AB > AC. | E is the mid-point of BC | and AD is perpendicular to BC

In triangle ABC, AB > AC. E is the mid-point of BC and AD is perpendicular to BC.
Prove that
AB2 + AC2 = 2.AE2 + 2.BE2Solution: In &#x2206 ABD AB2= AD 2 + BD 2
Or AB2= AD 2 + (BE + ED ) 2
Or AB2= AD 2 + BE 2 + 2. BE . ED + ED 2
Or AB2= AE 2 + BE 2 + 2. BE . ED -----(i)
OR AC2= AD2 + ( CE - ED) 2
Or AC2= AD2 + CE 2 - 2. CE . ED + ED 2
Or AC2= AE2 + CE 2 - 2. CE . ED ------(ii)
Adding equation 1 and situation 2 we have:
AB2 + AC2= AE2 + AE2 + BE2 + CE2 + 2. BE . ED - + 2. CE . ED
Or AB2 + AC2= AE2 + AE2 + BE2 + BE2 + 2. BE . ED - 2. BE . ED (As BE = CE )
∴ AB2 + AC2= 2 AE2 + 2BE2Proved

### Ratio Mathematics ICSE Tutorial Class 7

There are four videos of Ratio class 7. Few sums have also been explained with very easy steps. If there are any doubts then comment below. We will try to clear those doubts.

1. Understanding Ratio:

2. Comparing Ratio Basic and Shortcut method:

3. Compound Ratio , continued Ratio Dividing a number in a given Ratio:

4. Solution of few problem of ratio:
These sums of Ratio class 7 have been discussed in this video:
1. write in simplest form
72:108, 1/6:1/2,
15cm to 4m.
2. Population of a village is 32400. The ratio of literate
to illiterate person in the village is 11:7. Find the actual number of literate person and illiterate person. .
3. If a, b and c are three numbers such that a:b=4:9 and b:c=27:35. Find a:c
4. In what ratio should we increase 650 to obtain 1000.