Question

A box whose mass is $5\, kg$ lies on a spring balance inside a lift. The lift starts to ascend with an acceleration of $2\, ms ^{-2}$. The reading of the machine or balance is $\left(g=10\, ms ^{-2}\right)$

• A. 50 kg
• B. zero
• C. 49 kg
• D. 60 kg

Answer 1

Answer: (D)

60 kg

Answer 2

Reading $=m g +m a=5 \times 10+5 \times 2=60\, kg$