What acceleration will all objects experience during their flights through the air (on Earth)?

9.8 m/s/s

Explanation:

As such, all objects free fall at the same rate regardless of their mass. Because the 9.8 N/kg gravitational field at Earth's surface causes a 9.8 m/s/s acceleration of any object placed there, we often call this ratio the acceleration of gravity

a longitudinal wave moves energy that is to the direction of the wave’s movement. - true

we need to know the time interval during which the force acts. impulse of force = momentum change