Here's why:

* Propelled into the air: This means the object received an initial force that set it in motion upwards.

* No power to keep itself in air: This indicates the object has no engine or other means of generating thrust to counteract gravity.

Examples of projectiles:

* A ball thrown upwards

* A bullet fired from a gun

* A rocket after its fuel is spent

* A cannonball

Let me know if you'd like more details on projectile motion!