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Assume that a tiny and shiny (perfect conductor) Au metal in free space has a shape of a thin cylinder of thickness 1 m (like a tiny coin of thickness 1m) and end cap area of 500 m2. A monochromatic laser light having flux of energy 1 kW/m2 is normally incident on one of the end caps of this tiny metal. Find the maximum acceleration that this metal piece can attain under the action of this monochromatic laser light.

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Welcome to Physics.SE, Marie. Out FAQ says that we con't answer question that look like homework assignments, which includes this one. However, we would be happy to address a question about the underlying physics. If you would care to edit this to ask about the momentum assocaited with a monochromatic beam of light and/or how much of it can be reflected we could re-open this question and you could get some help. – dmckee♦ Dec 23 '12 at 23:52
For that matter it may be enough to help you if I emphasize that light carries momentum, and the reflection of light therefore transfers momentum to the reflecting object. Perhaps you can work the problem from there. Look in your textbook or on the internet for how much mometum. – dmckee♦ Dec 23 '12 at 23:54
The problem is in my textbook(Griffiths) I could not find any relevant topic for this problem, can you please at least tell me which topic is it about – Marie Dec 24 '12 at 0:00
Light carries momentum. When light is absorbed or reflected the stuff that does the absorbing or reflecting gets that momentum added to the momentum it had before. That is, the cylinder's momentum is going to be changing, which means it is accelerating. You have been asked to calculate the largest possible value of that acceleration, which you will get by comparing the largest possible rate of change of momentum to the mass of the object. – dmckee♦ Dec 24 '12 at 0:03
If there is some part of that explanation that is unclear, then please edit the question so that it asks about the concept that you are stuck on instead of just copying the problem for us. Then we can re-open this question and get several people to weigh in on the answer. – dmckee♦ Dec 24 '12 at 0:05
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closed as too localized by dmckee♦ Dec 23 '12 at 23:53

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