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Mechanics
23 Nov 2007 19:13:35 IST
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New Challenge (IIT'92)
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5 Salutes to one who gets it right.
(No Diagram given)
Q)A sledge filled with sand slides down without friction down
a 300 slope.Sand leakes out through a hole in the sledge at
a rate of 2 Kg per second.If the Sledge starts from rest
from the top of inclineand if total initial mass of Sledge is
40 Kg, How long does it take to go down 120 metre in the
plane?
Everyone who gives a good effort will be rated.
Solution will be posted tomorrow by 4.00 pm.
ALL THE BEST.....WISH YOU ALL GOOD LUCK.
Comments (63)
23 Nov 2007 23:24:18 IST
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In the end : (linkin Park)
Just Joking I was going to say....that
"IN THE END NO ONE WAS A LOSER"
"EVERYONE BENEFITED FROM IT".........I HOPE SO
AND I APPRECIATE EVERYONE'S PARTICIPATION.
AWESOME RESPONSE.
THANK YOU !!!!!!!!!!!ALL!!!!!!!!!
CHEERS!!!!!!!!!!!AND GOOD NIGHT!!!!!!!!!!!!!
Just Joking I was going to say....that
"IN THE END NO ONE WAS A LOSER"
"EVERYONE BENEFITED FROM IT".........I HOPE SO
AND I APPRECIATE EVERYONE'S PARTICIPATION.
AWESOME RESPONSE.
THANK YOU !!!!!!!!!!!ALL!!!!!!!!!
CHEERS!!!!!!!!!!!AND GOOD NIGHT!!!!!!!!!!!!!
24 Nov 2007 11:44:49 IST
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even if the sledge is considered massless (as assumed in the problem) :
the problem uses change in momentum to calculate force
after 20 s there is no change in momentum so no force applied as we know no force acts on a massless body
but it will have its velocity
so it should be covering the remaining distance with a constant velocity taking a total of 38 sec
the problem uses change in momentum to calculate force
after 20 s there is no change in momentum so no force applied as we know no force acts on a massless body
but it will have its velocity
so it should be covering the remaining distance with a constant velocity taking a total of 38 sec
6 Dec 2007 19:16:10 IST
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Dude,
The sand is leaking out from the sledge at the rate of 2kg/s
as it has been given in th Question.
So the change in mass every sacond will be:
(M+40-2t)
Here M=mass of sledge as assumed by :"BIKI"
40 kg = weight of sand in the sledge.
So totla initial mass=M+40 kg.
And then he has given the conservation of momentum eq:
(M+40-2t)V - M+40-2(t+dt)V = F.dT
Here t+dt as assuming that the mass of sand that has
leaked out in small interval "dt" to be very small.
Hope you find it useful.
Rate if useful.
Cheers!!!!!!!!@@@!!!!!!!!!
The sand is leaking out from the sledge at the rate of 2kg/s
as it has been given in th Question.
So the change in mass every sacond will be:
(M+40-2t)
Here M=mass of sledge as assumed by :"BIKI"
40 kg = weight of sand in the sledge.
So totla initial mass=M+40 kg.
And then he has given the conservation of momentum eq:
(M+40-2t)V - M+40-2(t+dt)V = F.dT
Here t+dt as assuming that the mass of sand that has
leaked out in small interval "dt" to be very small.
Hope you find it useful.
Rate if useful.
Cheers!!!!!!!!@@@!!!!!!!!!
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yaar i think its acceleration is always less than gsin30
so time taken should come >6.99 as it comes by taking a=gsin30
so 1.23 s can never be a soln
its only a biproduct of the quadratic