Question

After a projectile is fired into the air, what is the acceleration in the x-direction? (Assume no air resistance.)

Answer 1

Without air resistance, there is no horizontal force on the projectile,
so it has no horizontal acceleration. The answer is "zero".

Answer 2

`a_x = 0`

Step-by-step explanation:

When projectile is in air then the force on the projectile is only due to its weight

It is vertically downwards

`F_g = mg(-\hat j)`

so here since we don't have any air drag or friction due to air so there will be no force along its tangent or along x direction

so the acceleration along x direction will be zero

`a_x = 0`

`a_y = - g`