Subject: Is it possbile to make a compact magnetic switch?

I am working on my final term project and i am interested in the possibility 
of creating a economical and efficient method of physically opening and 
closing a small lightweight flap.  It would be a relatively easy to use a 
small toy motor and a series of gears - however, i worry about the long term 
use and possible breakdown of this type of switch. overtime.  As a result, I 
wanted to look into the possibility of using magnets to open (through the use 
of repulsive forces) and close (through attractive forces) of this lightweight 
flap.  My question is multi-faceted:
1)would the current needed to reverse the polarity of the magnets be less than 
that used to power a small toy motor?  
2)How do I calculate the energy needed to create the required force? (which i 
understand would be a factor based on the object i was trying to move)
3) how long does the current have to be running through the magnet to change 
its polarity?
4) Which type of magnets are suitable for this use?


thank you kindly in advance. I look forward to hearing from one of your 
scientists.  This is a great service, and I have enjoyed reading the questions 
and answers relevant to my questions.

Best regards,
Emmet
 

Re: Is it possbile to make a compact magnetic switch?