Question

what is the balls horizontal velocity at t = 3 seconds? justify your answer.

Explanation:

Step1: Identify horizontal - motion property

In projectile motion, horizontal velocity ($v_x$) is constant when there is no horizontal acceleration (neglecting air - resistance).

Step2: Determine initial horizontal velocity

Given that the initial horizontal velocity $v_{x0}=12$ m/s.
Since there is no horizontal acceleration ($a_x = 0$), the horizontal velocity at any time $t$ is equal to the initial horizontal velocity.
So, $v_x(t)=v_{x0}$.

Step3: Find horizontal velocity at $t = 3$ s

Substitute $t = 3$ s into the horizontal - velocity formula. Since $v_x(t)=v_{x0}$ and $v_{x0}=12$ m/s, then $v_x(3)=12$ m/s.

Answer:

The ball's horizontal velocity at $t = 3$ seconds is 12 m/s. Justification: In projectile motion with no horizontal acceleration (neglecting air - resistance), the horizontal velocity remains constant throughout the motion, and the initial horizontal velocity is 12 m/s.