Question

what is trajectors and horizontally

Answer 1

A projectile is any object upon which the only force is gravity,

Projectiles travel with a parabolic trajectory due to the influence of gravity,

There are no horizontal forces acting upon projectiles and thus no horizontal acceleration,

The horizontal velocity of a projectile is constant (a never changing in value),

There is a vertical acceleration caused by gravity; its value is 9.8 m/s/s, down,

The vertical velocity of a projectile changes by 9.8 m/s each second,

The horizontal motion of a projectile is independent of its vertical motion.