sign up I login
 advanced
refer a friend - earn nickels!!

Ask & Discuss Questions with Community & Experts

Moderation Team
 90 chars left    advanced
Ask iit jee aieee pet cbse icse state board community Community Discussion Question: some doubtful questions..please tell true or false!!
Forum Index -> Mechanics like the article? email it to a friend.  
Author Message
joyfrancis (1504)

Blazing goIITian

Olaaa!! Perrrfect answer. 236  [398 rates]

joyfrancis's Avatar

total posts: 1801    
offline Offline
1)a pipe ABCD is bent into three sections horizontal AB vertical BC (C below B) and horizontal CD . In AB liquid flowing velocity is v1 and pressure is p1 similarly it is v2,p2 in CD then ... v1=v2 dn p1=p2 TRUE OR FALSE!!
 
2)the kinetic energy of a gas molecule is 3PV/2 for monoatomic gas only- T/F
 
3)a stick is thrown in air then the CM will travell in parabolic path in all cases - T/F
 
 

There is no better feeling in this world than being a winner!
    
raman123 (5)

New kid on the Block

Olaaa!! Perrrfect answer. 1  [1 rates]

raman123's Avatar

total posts: 8    
offline Offline
F,T,T
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
joyfrancis (1504)

Blazing goIITian

Olaaa!! Perrrfect answer. 236  [398 rates]

joyfrancis's Avatar

total posts: 1801    
offline Offline
WHAT WOULD BE THE ANSWER TO THE FIRST ONE!
VI=V2 IS CORRECT FOR SURE SINCE AREA IS UNIFORM. PI AND P2 MEIN KYA RELATION HAI?

There is no better feeling in this world than being a winner!
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
Prakriteesh (153)

Scorching goIITian

Olaaa!! Perrrfect answer. 21  [45 rates]

Prakriteesh's Avatar

total posts: 231    
offline Offline
 From Bernoulli's equation:
    P1 +  1/2 v12 + gh1 = P2 +  1/2 v22 + gh2
As v1 = v2
So , the equation reduces to :
     P1 + gh1 = P2 + gh2
But since h1 is not equal to h2
So,  P1 not equal to P2
Hence false.
 
II)    No single gas molecule can have 3/2.PV. The energy of one gas molecule (ideal gas irespective of whether it is monoatomic or diatomic) is 3PV/2NA.
Hence false.
 

Let us build a new world with love, peace, happiness and engineering! (DON'T CHOOSE THE ODD ONE OUT)

Freshman, Bits-Pilani Goa Campus (Msc Physics)




Animated Letters
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
Prakriteesh (153)

Scorching goIITian

Olaaa!! Perrrfect answer. 21  [45 rates]

Prakriteesh's Avatar

total posts: 231    
offline Offline
It is not given in the question that the c.s.area of the pipe is uniform.

Let us build a new world with love, peace, happiness and engineering! (DON'T CHOOSE THE ODD ONE OUT)

Freshman, Bits-Pilani Goa Campus (Msc Physics)




Animated Letters
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
arsenal2007 (22)

Hot goIITian

Olaaa!! Perrrfect answer. 2  [8 rates]

arsenal2007's Avatar

total posts: 105    
offline Offline
how last one is true

consider the case of stick going directy upwards

plz don't forget to rate me

<TABLE CELLSPACING="1" CELLPADDING="1" BORDER="0">
<TR><TD>


<DIV ALIGN="right">Animated Letters</DIV></TD></TR></TABLE>
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
catch_arnnie (521)

Blazing goIITian

Olaaa!! Perrrfect answer. 81  [139 rates]

catch_arnnie's Avatar

total posts: 444    
offline Offline
for first:: p2 should be greater that p1, & v1 should be equal to v2..

for 2nd:: 1/3mnu^2 = pv -->according to kinetic theory

so, kinetic energy should be 3pv/2 irrespective of no. of atoms in a molecule of the gas...

for 3rd:: the center of mass is constant, so if we just consider the center of mass, then it will be a point following a parabolic path...

PLEASE RATE MY ANSWERS IF YOU FIND THEM USEFUL...
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
Prakriteesh (153)

Scorching goIITian

Olaaa!! Perrrfect answer. 21  [45 rates]

Prakriteesh's Avatar

total posts: 231    
offline Offline
 The second one is false because in the question it is asked about the kinetic energy of one single molecule. Moreover there is no requirement of being monoatomic, the gas just has to be ideal.
The third one is correct.

Let us build a new world with love, peace, happiness and engineering! (DON'T CHOOSE THE ODD ONE OUT)

Freshman, Bits-Pilani Goa Campus (Msc Physics)




Animated Letters
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
nick (462)

Scorching goIITian

Olaaa!! Perrrfect answer. 74  [120 rates]

nick's Avatar

total posts: 247    
offline Offline
the third one has to be true...

it is because there is no EXTERNAL force to "disturb" the COM and hene it will continue to move in the original path....

IIT- Imposible Is This(atleast fr meeeeeeeee)
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
arsenal2007 (22)

Hot goIITian

Olaaa!! Perrrfect answer. 2  [8 rates]

arsenal2007's Avatar

total posts: 105    
offline Offline
how do you know it has been thrown at a some angle

plz calrify

plz don't forget to rate me

<TABLE CELLSPACING="1" CELLPADDING="1" BORDER="0">
<TR><TD>


<DIV ALIGN="right">Animated Letters</DIV></TD></TR></TABLE>
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
joyfrancis (1504)

Blazing goIITian

Olaaa!! Perrrfect answer. 236  [398 rates]

joyfrancis's Avatar

total posts: 1801    
offline Offline
hey arnnie.
Kinetic energy for monoatomic and diatomic gases are different.
KE=fRT/2 or fPV/2
monoatomic has f=3 while diatomic has f=5
so A,C options both seem correct .. what is wrong??...
options are
A)3pv/2 for monoat. gas only
B)3pv/2 for diat. gas only.
C)>3PV/2 for diat.
D)3PV/2 in all cases.

@prakriteesh
the kinetic energy of a single molecule is fiven by fR/2 and kinetic energy per mole is fKt/w(K being the botlzman const)
 
@arsenal..(liverpool rules btw)
the stick being thrown exactly upwards is noot considered as an ideal condition, it is not possible to throw it directly upwards. moreover the options were..
a)in all cases
b)only if stick is uniform
c)only if stick is not rotating
d)only if com is INSIDE the body and not at any point outside it.
 
You are right in saying that if we are able to throw is directly up the com wouldtravell in a straight line. But seeing the options that case is rejected!!

There is no better feeling in this world than being a winner!
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
catch_arnnie (521)

Blazing goIITian

Olaaa!! Perrrfect answer. 81  [139 rates]

catch_arnnie's Avatar

total posts: 444    
offline Offline
joy, according to your statement i can draw a conclusion of just option A) coz' diatomic gases cannot hav KE=4pv/2 which is included in option C) so, A) must be correct



P.S. i think i have done this question wrong in the exam..

PLEASE RATE MY ANSWERS IF YOU FIND THEM USEFUL...
 this reply: 0 points  (with Olaaa!! Perrrfect answer.   in 0 votes )   [?]
 
You have to be logged on to rate
  
 
Forum Index -> Mechanics
Go to:   

 Aakash Institute IIT/ AIEEE/ Medical Crash Course
Name  
E-mail  
Phone  
Mobile  
** Hurry. Exclusive goIIT Offer. Limited Seats Only!
available in: New Delhi, Amritsar, Bhatinda, Bokaro, Chandigarj, Dehradun, Guwhati, Hyderabad, Indore, Jaipur, Kanpur, Karnal, Kolkata, Kota, Lucknow, Ludhiana, Mumbai, Noida, Patiala, Patna, Pune, Ranchi, Varanasi
Top Offers for goIITians
Correspondence Courses