Answer
We can rank the arrangements according to the magnitude of the net force on the block, from largest to smallest:
$(3) \gt (2) \gt (1)$
Work Step by Step
Let $k$ be the spring constant of each spring.
Arrangement (1):
If the block is displaced by a distance $d$ to the left, the two springs are compressed by a distance $d$. Each spring exerts a force on the block directed to the right. The magnitude of each force is $kd$. The magnitude of the net force on the block is $2kd$
Arrangement (2):
If the block is displaced by a distance $d$ to the left, the two springs on the left are compressed by a distance $d$. The spring on the right is stretched by a distance $d$. Each spring exerts a force on the block directed to the right. The magnitude of each force is $kd$. The magnitude of the net force on the block is $3kd$
Arrangement (3):
If the block is displaced by a distance $d$ to the left, the two springs on the left are compressed by a distance $d$. The two springs on the right are stretched by a distance $d$. Each spring exerts a force on the block directed to the right. The magnitude of each force is $kd$. The magnitude of the net force on the block is $4kd$
We can rank the arrangements according to the magnitude of the net force on the block, from largest to smallest:
$(3) \gt (2) \gt (1)$
