Question

A boy whose mass is 50kg stands on a spring balance inside a lift. The lift starts to ascent with an acceleration of $2ms^{- 2}.$ The reading of the machine or balance $(g = 10ms^{- 2})$ is

• A. $50kg$
• B. Zero
• C. $49kg$
• D. $60kg$

Answer 1

Answer: (D)

$60kg$

Answer 2

$R = m(g + a) = 50 \times (10 + 2) = 600N = 60kgwt$