A block of mass \( 10 kg \) is suspended inside a lift with the help of two identical vertical springs, as shown in the figure. When the lift is at rest, tension in the lower spring is \( 10 N \) and it is stretched. What is the magnitude of the acceleration (in \( m / s ^{2} \) ) of the lift so that to make the tension in the lower spring equal to zero? (Take \( g =10 m / s ^{2} \) )
