Define extiency of a liever

Astone dropped into a well is heard to strike the water after 8seconds. find the depth of the well if the velocity of sound is 350m/s

Argon is adiabatically compressed from an initial volume of 16 liters to a final volume of 2 liters. by what factor do the following quantities change? do they increase or decrease? (a) the rms speed (b) the thermal energy of the gas (c) the molar specific heat cv (d) the pressure

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?