A baseball pitch leaves the pitcher's hand horizontally at a velocity of 170 km/h .

Question

By what % will the pull of gravity change the magnitude of the velocity when the ball reaches the batter, 18 m away? For this estimate, ignore air resistance and spin on the ball.

Answer 1

Trick question! Imagine a ball that was just thrown by a pitcher - what happens to that ball? Of course it'll move sideways at the speed at which it was thrown, and it'll start to fall down, but gravity won't slow down the ball's horizontal velocity.

So the answer is 0% - the ball will still be moving 170 km/h when it hits the pitcher (this is of course incorrect in the real world, because air will slow the ball. The effect of air on baseballs is called "drag" if you ever want to spend some time Googling that effect - it's quite interesting!)