Question 203: Laws of Motion

Question

The weight of a man in a lift moving upwards with an acceleration 'a' is 620 N. When the lift moves downwards with the same acceleration, his weight is found to be 340 N. The real weight of the man is

Accepted Answer

W$$_1$$ = 620 N, W$$_2$$ = 340 N
W$$_1$$ = m(g + a) ..... (i)
W$$_2$$ = m(g $$-$$ a) ..... (ii)
$$	herefore \mathrm{\frac{W_1}{W_2}=\frac{620}{340}=\frac{g+a}{g-a}}$$
$$	herefore \frac{31}{17}=\mathrm{\frac{g+a}{g-a}}$$
Solving : $$\mathrm{a=\frac{7}{24}g}$$
Putting this value in Eq. (i) and solving we get mg = 480 N

Answer

620 N

Answer

680 N

Answer

380 N

Answer

480 N

Laws of Motion

The weight of a man in a lift moving upwards with an acceleration 'a' is 620 N. When the lift moves downwards with the same acceleration, his weight is found to be 340 N. The real weight of the man is

Choose the correct answer: