Question

A mercury barometer reads 75 cm in a stationary lift. what is the reading does it show when the lift is moving downwards, with an acceleration of 1 m/s^2..????

Answer 1

here we have to use Pseudo force connect,
acceleration , a = 1 m/s² is downward so, net acceleration is , anet = (g - a) downward.
now formula will be ,
ρgh' = ρ(g - a)h
Here, h' is final height of barometer ,
⇒ h' = h( 1 - a/g)
Now, put a = 1m/s², g = 10m/s² and h = 75 cm
h' = 75( 1 - 1/10) = 75 × 9/10 = 67.5 cm

Hence, 67.5 cm is the reading does it show when the lift is moving downward , with acceleration of 1 m/s²

Answer 2

Answer:83.33cm

Explanation:

At the time when lift is stationary it reads 75 cm..this means the Po = 75xdensityxg

Now,

the lift is moving downward with acceleration 'a'

Po = hxdensityx(g-a)

75xdensityxg = hxdensityx(g-a)

h = 750/9

h = 83.33cm