A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring balance reads $49 \mathrm{~N}, when the lift is stationary. If the lift moves downward with an acceleration of 5 \mathrm{~m} / \mathrm{s}^2, the reading of the spring balance will be \left(g=9.8 \mathrm{~m} / \mathrm{s}^2\right)