$A$ barometer kept in a stationary elevator reads $76 \ cm$. If the elevator starts accelerating upwards,the reading will be:

The value of $g$ at a place decreases by $2\%$. The barometric height of mercury:

Describe the Torricelli experiment for the measurement of atmospheric pressure.

Consider the wall of a dam to be straight with height $H$ and length $L$. It holds a lake of water of height $h$ $(h < H)$ on one side. Let the density of water be $\rho_w$. Denote the torque about the axis along the bottom length of the wall by $\tau_1$. Denote also a similar torque due to the water up to height $h/2$ and wall length $L/2$ by $\tau_2$. Then $\tau_1 / \tau_2$ (ignore atmospheric pressure) is

The height of a mercury barometer is $75 \ cm$ at sea level and $50 \ cm$ at the top of a hill. The ratio of the density of mercury to that of air is $10^4$. The height of the hill is ....... $km$.

$A$ submarine is designed to withstand an absolute pressure of $100 \text{ atm}$. How deep can it go below the water surface (in $\text{ m}$)? (Consider the density of water = $1000 \text{ kg/m}^3$, $1 \text{ atm} = 1 \times 10^5 \text{ Pa}$, and gravitational acceleration $g = 10 \text{ m/s}^2$)