physics question...help?

Question

1. A stone is thrown, no air resistance. what is its vertical acceleration & its horizontal acceleration?
2. why an airplane moving through the air is not an example of projectile motion?

Answer 1

1. 9.8 m/s^2 downwards (32.2 ft/s^2). 0 horizontal.

2. the horizontal movement of air along the wing surfaces is transformed into vertical lift. In order to keep the plane flying, horizontal speed is sacrificed (said yet another way: horizontal kinetic energy is used up in preventing downward fall).

In a projectile, horizontal speed remains the same (except for air resistance) while vertical varies according to gravity.

If the plane is motorized (as opposed to a glider), then a propulsion system can 'replenish' the horizontal energy by keeping the plane at a steady speed. In level flight, the motor must provide the energy that is lost to making lift (and combatting air resistance).

Answer 2

The plane isnt a projectile because no outside force forced it to move- it moves on its on power.