Question

Please see this image ----https://www.dropbox.com/s/4zlk239kx8wbgqa/20191011_105927.jpg?dl=0
I can not put the image in here, so I created the dropbox link and thanks in advance for your help :)

Answer 1

The vertical part of the rope is shortened with acceleration $(3+4)m/s^2$ .

 when the length of the vertical part of the rope decreases by $x$ meters the height of the block C increases by $x/2$ meters, hence acceleration of the block C is $(3+4)/2\ m/s^2=3.5\ m/s^2$

Answer: $3.5\ m/s^2.$