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a baseball is hit upward and travels along a parabolic arc before it strikes the ground. which one of the following statements is necessarily true?
the acceleration of the ball decreases as the ball moves upward.
the x - component of the velocity of the ball is the same throughout the balls flight.
the acceleration of the ball is zero m/s² when the ball is at the highest point in the arc.
the velocity of the ball is zero m/s when the ball is at the highest point in the arc.
the velocity of the ball is a maximum when the ball is at the highest point in the arc.

Explanation:

In projectile - motion (like the baseball's motion), the horizontal (x - component) of velocity remains constant because there is no horizontal acceleration (neglecting air - resistance). The acceleration due to gravity is constant throughout the motion ($g\approx9.8\ m/s^{2}$), so the acceleration of the ball does not decrease as it moves upward. At the highest point of the arc, the vertical component of velocity is zero, but the horizontal component is non - zero, and the acceleration is still $g$ downward. The velocity is minimum at the highest point of the arc.

Answer:

The x - component of the velocity of the ball is the same throughout the ball's flight.