Question

If the lift in problem, moves up with an acceleration equal to the acceleration due to gravity, the reading on the spring balance will be

• A. 2 kg
• B. (2 ×g) kg
• C. (4 ×g) kg
• D. 4 kg

Answer 1

Answer: (C)

(4 ×g) kg

Answer 2

$R = m(g + a)$ $= m(g + g)$

[because the lift is moving upward with a =g]

$= 2mgR = 2 \times 2gN$ $= 4gN$or $4kg$