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Mission VP10 Displacement and Time for a Projectile

 The Question

A truck drives down the road at a constant speed. A ball is launched from the back of the truck. By the time the ball returns to its original launch height, the truck is at the position shown. Assuming negligible air resistance on the ball, the ball would follow path ... .

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 Physics Rules

Independence of Perpendicular Components of Motion
Perpendicular components of an object's motion are independent of each other. For a projectile, the horizontal motion is independent of the vertical motion. The horizontal motion occurs at a constant speed. The vertical motion occurs with a downward acceleration. The two motions are independent of each other.

 Think About It

If we can assume negligible air resistance on the ball, then the ball travels as a projectile. The projectile's motion can be described as having a constant horizontal motion and an accelerated vertical motion. The constant speed in the horizontal direction means that in the same amount of time, the ball will travel the same horizontal distance as the truck. Thus, at all locations in its trajectory, the ball is directly above the launcher of the truck. And when the ball returns to the truck, it will hit the truck at the same location in the truck from where it was launched.

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