A man of mass 60 kg is riding in a lift. The weight of the man, when the lift is accelerating upwards and downwards at 2 ms-2, are respectively . (Taking g = 10 ms-2)

Question

A man of mass 60 kg is riding in a lift. The weight of the man, when the lift is accelerating upwards and downwards at 2 ms-2, are respectively . (Taking g = 10 ms-2) (A) 720 N and 480 N (B) 480 N and 720 N (C) 600 N and 600 N (D) None of the above

Tardigrade Admin · Accepted Answer

When the lift is accelerating upwards with a constant acceleration a, then
weight, w = m(g + a)

= 60 (10 + 2) = 60 \times 12

= 720 N

When the lift is accelerating downwards at the rate a, then
weight, w' = m(g - a)

= 60 (10 - 2) = 60 \times 8

= 480 N

Q. A man of mass 60 kg is riding in a lift. The weight of the man, when the lift is accelerating upwards and downwards at 2 ms−2, are respectively . (Taking g = 10 ms−2)

720 N and 480 N

480 N and 720 N

600 N and 600 N

None of the above

When the lift is accelerating upwards with a constant acceleration a, then weight, w = m(g + a) =60(10+2)=60×12 =720N When the lift is accelerating downwards at the rate a, then weight, w' = m(g - a) =60(10−2)=60×8 =480N

Q. A man of mass 60 kg is riding in a lift. The weight of the man, when the lift is accelerating upwards and downwards at 2 $m s^{- 2}$ , are respectively .
(Taking g = 10 $m s^{- 2})$

When the lift is accelerating upwards with a constant acceleration a, then
weight, w = m(g + a)
$= 60 (10 + 2) = 60 \times 12$
$= 720 N$
When the lift is accelerating downwards at the rate a, then
weight, w' = m(g - a)
$= 60 (10 - 2) = 60 \times 8$
$= 480 N$