Two boxes, A and B, are connected to each end of a light vertical rope, as shown in the following figure. A constant upward force 78.0N is applied to box A . Starting from rest, box B descends 12.3 m in 3.80s . The tension in the rope connecting the two boxes is 30.0 N

Question

Two boxes, A and B, are connected to each end of a light vertical rope, as shown in the following figure. A constant upward force 78.0N is applied to box A . Starting from rest, box B descends 12.3 m in 3.80s . The tension in the rope connecting the two boxes is 30.0 N 
What is the mass of box B?

drwls · Answer

One post is enough. The "following figure" is missing.

Anonymous · Answer

Mass of a is 6.7 Mass of b is 2.2

hg · Answer

yut