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![[Post New]](/templates/default/images/icon_minipost_new.gif) 22 Apr 2008 10:17:00 IST
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An Object is kept at 30cm from concave mirror of focal length 20cm.If mirror starts moving towards the object with velocity 2cm/s then find instantaneous velocity of image.
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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 |
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22 Apr 2008 12:14:59 IST
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Aapatsu Magnah Smaranam Tvadeeyam Karomi Durge Karunarna Veshi I
Naitaccha Thatvam Mum Methah Kshudhartrisharta Jananim Smaranti II
Jagdamb Vichitramatra Kim Paripoorna Karunaasti Chenmayi I
Aparadha Parampara Param Na Hi Mata Samupekshate Sutam II |
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22 Apr 2008 12:17:15 IST
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sorry mate wrong answer
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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 |
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22 Apr 2008 12:21:34 IST
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edited
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Aapatsu Magnah Smaranam Tvadeeyam Karomi Durge Karunarna Veshi I
Naitaccha Thatvam Mum Methah Kshudhartrisharta Jananim Smaranti II
Jagdamb Vichitramatra Kim Paripoorna Karunaasti Chenmayi I
Aparadha Parampara Param Na Hi Mata Samupekshate Sutam II |
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22 Apr 2008 12:22:25 IST
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sorry mate wrong answer
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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 |
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22 Apr 2008 12:26:11 IST
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i think the answer is 2cm/sec
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krishna |
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22 Apr 2008 12:26:16 IST
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then ...... correct 1??????????
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Aapatsu Magnah Smaranam Tvadeeyam Karomi Durge Karunarna Veshi I
Naitaccha Thatvam Mum Methah Kshudhartrisharta Jananim Smaranti II
Jagdamb Vichitramatra Kim Paripoorna Karunaasti Chenmayi I
Aparadha Parampara Param Na Hi Mata Samupekshate Sutam II |
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22 Apr 2008 12:26:53 IST
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is it correct if correct plsssssss accept my answer
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krishna |
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22 Apr 2008 12:27:19 IST
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do not forget to rate me
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krishna |
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22 Apr 2008 12:41:26 IST
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no wrong answer
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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 |
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for concave mirror 1/u + 1/v = 1/f differentiating -1/u^2du/dt - 1/v^2dv/dt = 0 => velocity of image = - (v/u)^2velocity of object Note:both are w.r.t to mirror now to find v we use the mirror equation 1/v + 1/(-30) = 1/(-20) => 1/v = 1/30 - 1/20 = -1/60 so v = -60 so (v/u)^2 = (60/30)^2 = 4 so velocity of image w.r.t mirror = -4*2 = -8cm/sec so velocity of image w.r.t ground = -8 - 2 = -10cm/sec so velocity of image is 10cm/sec in the same direction as the velocity of mirror
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"Imagination is more important than knowledge."
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22 Apr 2008 12:53:36 IST
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right answer Priyesh
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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 |
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22 Apr 2008 13:03:41 IST
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1/u + 1/v = 1/f
differentiating
-1/u^2du/dt - 1/v^2dv/dt = 0
=> velocity of image = - (v/u)^2velocity of object
now to find v we use the mirror equation
1/v + 1/(-30) = 1/(-20)
=> 1/v = 1/30 - 1/20 = -1/60
so v = -60
so (v/u)^2 = (60/30)^2 = 4
so velocity of image w.r.t mirror = -4*2 = -8cm/sec
so velocity of image w.r.t ground = -8 - 2 = -10cm/sec
so velocity of image is 10cm/sec in the same direction as the velocity of mirr
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krishna |
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22 Apr 2008 13:04:26 IST
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