A spring balance is attached to the ceiling of a lift . A man hanga his bag on the spring and the spring reads49 N when the lift is stationery . If the lift moves downward with an accelration of 5m/s the reading of the spring balance will be

due to pseudo force if seen in the frame of reference of the moving elevator the total acceleration on the bag is 9.8 + 5 ~ 15m/s^2 wheres initially it was just 9.8 due to g.
So the weigth now becomes
w = 49*15/9.8 = 75N

given that spring balance reads 49N when lift is stationary i.e. . mg=49 . m=49/9.8 . m=5 kg . now lift is accelerating downward so the pseudo force will be in upper direction so the resultant force that spring balance will read will be . R= mg - ma . R= 49 - (5)(5) . R= 24N . so spring will read 24 N