How Everything Works
How Everything Works How Everything Works

Question 1325

When you throw a ball upward and claim that there is no upward force on it as it rises, why don't you count your hand? The ball was thrown up, so there was an upward force on it! I'm confused.
While you are throwing the ball upward, you are pushing it upward and there is an upward force on the ball. But as soon as the ball leaves your hand, that upward force vanishes and the ball travels upward due to its inertia alone. In the discussion of that upward flight, I always said "after the ball leaves your hand," to exclude the time when you are pushing upward on the ball. Starting and stopping demonstrations are often tricky and I meant you to pay attention only to the period when the ball was in free fall.

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