Physics - NLM Question with Solution | TestHub

The reading of the spring balance measures the apparent weight of the bag, which is equal to the tension in the spring.

When the lift accelerates upwards with acceleration $a$, the net force on the bag (mass $m$) is $ma$ upwards. Applying Newton's second law: $T-mg=ma$, where $T$ is the tension in the spring. Therefore, $T=m(g+a)$.