In the simulation above, as the projectile travels upward, how does the vertical velocity change? vertical velocity is zero. vertical velocity decreases. vertical velocity increases. vertical velocity remains the same.

Vertical velocity decreases.

Explanation:

The figure of the simulation is missing, however we can still answer. In fact, the problem tells us that the projectile is moving upward. We are only interested in the vertical velocity of the projectile, so we can consider only its vertical motion.

The vertical motion of the projectile is an accelerated motion, with constant acceleration g = 9.8 m/s^2, directed downward (acceleration due to gravity). The problem says that the projectile is still moving upward, so its velocity is directed upward. This means that the vertical acceleration is in the opposite direction of the vertical velocity: therefore, the vertical velocity must be decreasing, according to the equation

where v0 is the initial vertical velocity of the projectile, and t the time. Due to the negative sign in the formula, we see that as t increases, v(t) decreases.

it has to be b, about 97 percent.