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Offline missbeautiful789

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M1 question
« on: March 27, 2010, 04:29:23 pm »
A box of weight W rests on a platform. When the platform is moving upwards with an of acceleration ?, the normal contact force from the platform on the box has magnitude kW. When the platform is moving downwards with acceleration 2?, the box remains in contact with it. find the normal contact force in terms of k and W, deduce that k ? 3/2
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Offline astarmathsandphysics

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Re: M1 question
« Reply #1 on: March 27, 2010, 05:46:02 pm »
2 hours
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Offline astarmathsandphysics

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Re: M1 question
« Reply #2 on: March 27, 2010, 07:03:06 pm »
moving up res kW-W=Wa/g (1)
moving down W=W*2a/g so a=g/2
sub into (1) kW-W=W/2 so KW=3W/2 so k=3/2
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