F = mg = 240N = 24*10(m =24 ,g = 10)
now F= 220 = m*(g-a)
so lift is moving downward

Introduction:
When an object is suspended from a spring balance in a lift, the reading on the spring balance indicates the force exerted by the object due to gravity. If the reading on the spring balance changes while the lift is in motion, it indicates that there is an additional force acting on the object, which implies that the lift is moving.

Explanation:
The change in reading on the spring balance from 240 N to 220 N suggests that there has been a decrease in the force exerted by the object. This decrease in force can be attributed to the presence of an additional force acting on the object, which in turn implies that the lift is moving.

Key Points:
1. Initial reading on the spring balance: 240 N
2. Changed reading on the spring balance: 220 N

Analysis:
To understand why the change in reading indicates the lift is moving, we need to consider the forces acting on the object in the lift. In this case, there are two forces:
1. Force due to gravity: This force is always acting on the object and can be measured using the spring balance. The initial reading of 240 N indicates the force exerted by the object due to gravity.
2. Additional force: This force arises when the lift is in motion. When the lift accelerates or decelerates, there is an additional force acting on the object, which can be measured by the change in reading on the spring balance.

Conclusion:
The change in reading on the spring balance from 240 N to 220 N indicates that the lift is moving. The decrease in the force measured by the spring balance suggests the presence of an additional force acting on the object, which can only occur when the lift is in motion. Therefore, based on the change in reading, we can conclude that the lift is moving.