Kagan: The physics of a bad hop

From SABR member David Kagan at The Hardball Times on January 7, 2018:

When we watch a major league infielder collect a routine grounder and fire to first, I’m sure some of us think, “I coulda been a ballplayer.” It is when they have to deal with sharply hit one-hoppers that we feel much more comfortable sitting on the sofa, watching the big screen, rather than risking life and limb.

Check out this play by DJ LeMahieu on a ball that left the bat at 102 mph. He made the play despite not only the velocity of the ball, but it taking a bad hop as well.


I wanted to explore the physics of these bad hops. But before we get into that, perhaps we should understand the physics of a “good hop.” Andrew Dominijanni described good hops in two recent articles at The Hardball Times: The Physics and Timing of the Infield Bounce Throw and The Physics and Timing of the Outfield Bounce Throw. For his analysis, he used the standard equations describing the bounce of spinning ball. I include them here in case you are an “equation person.” If not, ignore them and skip to the next paragraph where I’ll attempt to explain them in English.

Read the full article here: https://www.fangraphs.com/tht/the-physics-of-a-bad-hop/

Originally published: January 7, 2019. Last Updated: January 7, 2019.