| Author |
Message |
![[Post New]](/templates/default/images/icon_minipost_new.gif) 15 Jan 2008 21:43:33 IST
|
|
|
a brick with dimensions 20cm * 10cm * 8cm has a mass of 5kg.it is lying on the longer base.it is made to lie with length vertical.the amount of W.D. is a 2J b 3J c 4J d 5J sorry folks but don't know the answer
|
there are numerous options besides I.I.T
<TABLE CELLSPACING="1" CELLPADDING="1" BORDER="0">
<TR><TD>
   
<DIV ALIGN="right">Glitter Graphics</DIV></TD></TR></TABLE>
|
|
|
|
15 Jan 2008 22:05:17 IST
|
|
|
i m gettin c i.e 4J by applying centre of mass concept
|
Who says nothing is impossible.
I've been doing nothing for years !!..............
I know KUNG FU KARATE
and 47 other dangerous words.............
|
this reply: 2 points
(with 0 
in 1 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
15 Jan 2008 22:07:29 IST
|
|
|
show the solution
|
there are numerous options besides I.I.T
<TABLE CELLSPACING="1" CELLPADDING="1" BORDER="0">
<TR><TD>
<DIV ALIGN="right">Glitter Graphics</DIV></TD></TR></TABLE>
|
this reply: 0 points
(with 0
in 0 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
15 Jan 2008 22:21:59 IST
|
|
|
hmmm.............ok..........
initial position of centre of mass (10,5,4)
final position of centre of mass (4,10,5)
calculate modulus of displacement and multiply with mg and don't forget to chance cm in m...........
m not sure abt it...............just a guess
|
Who says nothing is impossible.
I've been doing nothing for years !!..............
I know KUNG FU KARATE
and 47 other dangerous words.............
|
this reply: 2 points
(with 0
in 1 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
15 Jan 2008 22:38:48 IST
|
|
|
the answer is 3J. solution: in the intial situation the CM was at height 4cm and in the final situation it was at height 10cm. therefore, work done is= (mghf-mghi)X10-2=3J
|
this reply: 5 points
(with 1
in 1 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
15 Jan 2008 22:43:13 IST
|
|
|
yes srk is right!!
|
<TABLE CELLSPACING="1" CELLPADDING="1" BORDER="0">
<TR><TD>
     
  
Anyone who has never made a mistake has never tried anything new
You can never solve a problem on the level on which it was created.
When you are courting a nice girl an hour seems like a second. When you sit on a red-hot cinder a second seems like an hour. That's relativity
Purpose of solving a problem is not simply to get the answer(the answer is only an evidence) but to develop your thinking ability |
this reply: 2 points
(with 0
in 1 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
15 Jan 2008 22:44:17 IST
|
|
|
well initially height of com is 4 cm
(height of brick is 8 cm so , height com is 4cm)
now when it lies with length vertical , height of com becomes 20/2=10 cm
so WD = mg(10cm - 4cm)
= 5*10 (0.1-0.04)
= 3J
|
The heights which great men reached and kept, Were not attained by sudden flight, They, whilst their companions slept, Were toiling upwards in the night.... |
this reply: 5 points
(with 1
in 1 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
15 Jan 2008 22:53:07 IST
|
|
|
Solution had been posted earlier check it
http://www.goiit.com/posts/list/mechanics-work-done-38838.htm
|
__________________________________________________________________________________________________________
From J.R.R. Tolkien's 'The Lord of the Rings':
All that is gold does not glitter
Not all who wander are lost
The old that is strong does not wither,
Deep roots are not reached by frost.
From ashes a fire shall be woken
From shadows a light shall spring
Renewed shall be blade that's broken
The crown less again shall be king. |
this reply: 5 points
(with 1
in 1 votes ) [?]
|
|
You have to be logged on to rate
|
|
|
|
|
Moderation Team
![[Up]](/templates/default/images/icon_up.gif "[Up]"){kind=icon}
2
