A 60kg man is inside a lift which is moving up with an acceleration of 2.45 ms^–2. The apparent percentage change in his weight is,

The apparent weight W=m(g+a)

So the percentage change of weight = $\frac{\mathrm{Apparent} \mathrm{weight}-\mathrm{orginal} \mathrm{weight}}{\mathrm{original} \mathrm{weight}}\mathrm{x}100$

=$\frac{\mathrm{m}(\mathrm{g}+\mathrm{a})-\mathrm{mg}}{\mathrm{mg}}\mathrm{x}100=\frac{2.45}{9.8}\mathrm{x}100=25\%$