A spring balance is attached to the ceiling of a lift. When the lift is at rest spring balance reads 49 N of a body hang on it. If the lift moves :
(i) Downward
(ii) upward, with an acceleration of `5ms^(-2)`.
(iii) with a constant velocity.
What will be the reading of the balance in each case ?

Explanation

(i) `R=m(g-a)`
weight =49N
so `m=(49)/(9.8) =5kg `
R=5(9.8-5)
R=24N
(ii) R=m(g+a)
R=5(9.8+5)
R=74N
(iii) as a=0 so R=mg =49N