Question

1. a projectile is in flight. assuming air resistance is negligible, what is the single force acting on the projectile in the vertical direction or y-direction?

there is an electro-magnetic force on the ball in the y-direction.
the cannon is putting a force on the ball in the y-direction even though the cannon is not touching the ball anymore.
there is no force on the ball in the y-direction.
gravity
clear all

Explanation:

To determine the force on a projectile in flight (negligible air resistance) in the vertical (y - direction):

1. Electro - magnetic force: There's no reason to assume an electromagnetic force acts on the projectile in the y - direction here, so this option is incorrect.
2. Cannon force: Once the projectile leaves the cannon, the cannon can no longer exert a force on it (since there's no contact), so this option is wrong.
3. No force: Gravity is a fundamental force that acts on objects near the Earth's surface, so there must be a force in the y - direction, making this option incorrect.
4. Gravity: When air resistance is negligible, the only force acting on a projectile in the vertical direction is gravity, which pulls the projectile downwards (in the negative y - direction, typically).

Answer:

D. Gravity