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From: ratchet | Reply 1 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 37 |
This happens because the frquency of the applied repeated periodic forced
vibrations becomes equal to the natural frequency of the rare view mirror
Posted at: Sun Dec 27 16:28:14 2009 (GMT)
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From: ratchet | Reply 2 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 38 |
The name of the phenomenon taking place is resonance
Posted at: Sun Dec 27 16:29:21 2009 (GMT)
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From: ratchet | Reply 3 of 22 | Reply | View replies (1)
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Subject: Contributed Answer/Explanation to Q. 39 |
In order to stop the violent vibrations we
Posted at: Sun Dec 27 16:30:39 2009 (GMT)
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From: ratchet | Reply 4 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 39 |
In order to stop the violent vibrations we can change the speed of the motor
bike or by tightening the screw of the rare view mirror
Posted at: Sun Dec 27 16:32:04 2009 (GMT)
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From: sourima | Reply 5 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 1 |
1:1
momentum for 1st body=20*5=100kg m\s^2
momentum of 2nd body=5*20=100kgm\s^2
therefore,ratio=1:1
Posted at: Thu Jan 7 17:30:00 2010 (GMT)
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From: ishan20 | Reply 6 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 8 |
focal length
Posted at: Mon Jan 18 02:31:48 2010 (GMT)
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From: abirghosh050793 | Reply 7 of 22 | Reply | View replies (1)
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Subject: Contributed Answer/Explanation to Q. 1 |
1 : 1
mp = 20 kg
vp = 5 m/s
mq = 5 m/s
vq = 20 kg
Ratio of the momenta of P and Q = mpvp : mqvq = 20 x 5 : 5 x 20 = 1 :
1
Posted at: Tue Feb 9 11:47:38 2010 (GMT)
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From: abirghosh050793 | Reply 8 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 1 |
1 : 1
mp = 20 kg
vp = 5 m/s
mq = 5 m/s
vq = 20 kg
Ratio of the momenta of P and Q = mpvp : mqvq = 20 x 5 : 5 x 20 = 1 :
1
Posted at: Tue Feb 9 11:48:50 2010 (GMT)
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From: abirghosh050793 | Reply 9 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 2 |
500 J
mp = 20 kg
vp = 5 m/s
Kinetic Energy of P = 1/2 mp (vp) 2 = 20 x 5 x 5 J = 500 J
Posted at: Tue Feb 9 11:53:15 2010 (GMT)
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From: abirghosh050793 | Reply 10 of 22 | Reply | View replies (1)
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Subject: Contributed Answer/Explanation to Q. 3 |
Fire tongs is an example of third class lever.
MA =
Effort Arm
Load Arm
Posted at: Tue Feb 9 11:56:46 2010 (GMT)
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From: abirghosh050793 | Reply 11 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 3 |
Fire tongs is an example of third class lever.
<p>
MA = Effort Arm / Load Arm
</p>
<p>
For a third class lever, effort is in between fulcrum and load, so,
</p>
<p>
Effort arm < Load arm
</p>
<p>
=> MA < 1
</p>
Posted at: Tue Feb 9 11:58:09 2010 (GMT)
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From: abirghosh050793 | Reply 12 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 4 |
In vacuum
Spring balance measures weight, not mass. In air weight of a body will be
less than in vacuum due to the buoyancy of air.
Posted at: Tue Feb 9 11:59:26 2010 (GMT)
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From: abirghosh050793 | Reply 13 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 6 |
It is because the specific latent heat of vaporisation of water is much
higher than its specific heat capacity.
Specific heat capacity of water = 4.2 J/g/oC
Specific latent heat of vaporisation = 2268 J/g
Heat needed to bring 'm' g of water to its boiling point from room
temperature (25oC) = m x 4.2 x (100 - 25) J = 315 m J
Heat needed to boil off 'm' g of water = m x 2268 J = 2268 m J
Let the power be P.
Time taken to bring 'm' g of water to its boiling point from room
temperature (25oC) = 315 m / P
Time taken to boil off 'm' g of water = 2268 m / P
Obviously, 2268 m / P is greater than 315 m / P.
Posted at: Tue Feb 9 12:08:29 2010 (GMT)
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From: abirghosh050793 | Reply 14 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 8 |
Focal Length
Only rays starting from the focus, after refraction emerges parallel to the
principal axis and fall normally on the plane mirror to get reflected back
in the same path. Thus the image is formed also on the focus. So, S is the
focus, and OS is the focal length
Posted at: Tue Feb 9 12:11:16 2010 (GMT)
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From: abirghosh050793 | Reply 15 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 9 |
on S
Here the phenonmenon of the return of the rays to their starting point is
independent of the distance between the lens and plane mirror.
Posted at: Tue Feb 9 12:12:47 2010 (GMT)
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From: abirghosh050793 | Reply 16 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 10 |
A piece of red-cloth appears red in white light because it absorbs blue and
green, and reflects only red.
White light mainly contains red green and blue colours. Anything which
absorbs blue and green, and reflects only red, will appear red in white
light as only red colour reaches our eyes.
Posted at: Tue Feb 9 12:15:21 2010 (GMT)
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From: abirghosh050793 | Reply 17 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 12 |
The far point of a normal person lie on the retina of his eyes, but for a
myopic person it lies in front of the retina
For a normal person the rays of light from a distant is focussed on the
retina, facilitating clear vision, but for a myopic person, the rays are
focussed in front of the retina, thus making distant vision blurred.
Posted at: Tue Feb 9 12:17:53 2010 (GMT)
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From: abirghosh050793 | Reply 18 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 14 |
No
Quality does not depend on the pitch, but on the waveform. If two different
persons play even on identical guitars, the number of ubsidiary notes
produced by them and their relative amplitudes with the principal note will
not exactly match. So, the quality of their sounds will differ, even if they
play notes of the same pitch.
Posted at: Tue Feb 9 12:21:17 2010 (GMT)
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From: shafeek47 | Reply 19 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 1 |
1:1
Posted at: Mon May 10 16:41:34 2010 (GMT)
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From: utsav13 | Reply 20 of 22 | Reply | |
Subject: Contributed Answer/Explanation to Q. 2 |
250 Joules
1/2 x 20 x 5 x 5 = 250 joules Posted at: Fri Feb 25 13:31:38 2011 (GMT)
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