Please solve some one.

Sums on Gravitation

 

1.Two masses m1 & m2 revolve round a common center of mass,forming a binary system.Show that the common time-period T is given by,T=2 ,where r is the distance of 2 ,masses.

2.The acceleration due to gravity at 2 places are g1 & g2.From the same height at 2 places if a body be dropped, it takes t less to reach the ground in the second place than the first, but the velocity on reaching the ground in the second place is greater by v than in the first place.Prove that g1g2=v^2/t^2.

Please solve.Rates assured......................

Sorry,the answer is wrong.Right answer is 1/4.By the way I have already done this sum so try to crack the other one please

Confusion in Gravitation::

Look at this sum------

Calculate the distance from the surface of the Earth at which above and below the acceleration due to Gravity is the same.

I have got the answer by equating the 2 conditions.But I cant understand how this can happen since we know that acc. due to gravity at a height h is same as acc. due to gravity at a depth x,where x=2h. 

Sums on Probability::::::::::

 

1.Find the probability that in 5 tossings a coin turns up head at least 3 times in succession.

2.From the no.s 1,2,.....................,(2n+1) 3 are selected at random.What is the prob. that this no.s are in A.P.

S1=50/2(2.2+(50-1)2)

S2=20/2(2.5+(20-1)5)

Then Find S1+S2

S3=10/2(2.10+(10-1)10)

Find S1+S2-S3

Sum on Probability:::::::::;

1)Five different letters are put inside 5 addressed envelopes by an illeterate servent.What is the probability that only 2 letters are placed in correct envelopes?

2)An urn contains 2 white & 2 black balls .Balls are drawn succesively wihout replacement.What is the probability that a black ball appears for the 2nd time in the 4th drawing?

Sum on Probability2

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There are 3 groups.The 1st group contains 3 girls & and 1 boy.The 2nd group contains 2girls and 2 boys whereas the 3rd contain 1girl and 3 boys.Another group is formed by picking one student from the existing groups.What is the probability that the goup formed will contain 1 boy & 2 girls.

Sum on Probability:::::::



 

The chance of a teacher to take a surprise test on a meet with his students is (1/5).A student remains absent for 2 consecutive meets.What is the probabilility that he will miss at least one test.

B.MAT

One year IIT and Two year ELITE students YG File Students PET		PET IV 31.08.2008
Part Test I	Part Test I 14.09.2008		(Mumbai and Pune 21.09.2008)
Part Test II		Part Test II 28.09.2008
Part Test III		Part Test III 12.10.2008
Part Test IV	Part Test IV 26.10.2008		(Pune 02.11.2008)
Part Test V		Part Test V 09.11.2008
Part Test VI		Part Test VI 23.11.2008

Plz show ur steps

Big time doubt with cocept of angular momentum

A particle is projected at time t=0 from a point P on the ground witha speed v,at an angle 45deg. to the horizantal.Find the magnitude and direction of the angular momentum of the particle about P at time t=v/g

Plz solve this rates assured.