Apparent Weight & Lift question from JEE Main 2025 (28 Jan, Shift 2)

Answer: (b)

1. Rising with $a$: $U - Mg = Ma \Rightarrow U = M(g + a)$.
2. After releasing $\Delta m$, rising with $3a$: $U = (M - \Delta m)(g + 3a)$.
3. $M - \Delta m = \dfrac{M(g + a)}{g + 3a} \Rightarrow \Delta m = \dfrac{2Ma}{3a + g}$
4. So the answer is (b) $\dfrac{2Ma}{3a+g}$.