Help me to answer this physic question?

Question

the diagram represents an ideal pulley system(no mass or friction)

what is the force, F required to lift the 45 kg mass?

the diagram u can view from this link

http://i21.photobucket.com/albums/b266/orizim/Image016.jpg

Answer 1

The weight of 45 kg is mg = (45 kg)(9.80 m/s^2) = 441 N

In your diagram, you have two lines lifting the weight.  The force, then, will be 441 N/2 = 220.5 N, ignoring significant digits.