Luckily, it's a linear relationship and they gave us the temp change per slap. So, if we assume the chicken has thawed in the fridge (40°F) and we want to reach 165°F for food safety, we only need

(165 - 40)°F * (5°C / 9°F) / (0.0089 °C / slap)
= 7803 slaps

Although, to be honest I think this would only work for a spherical chicken in a vacuum, as otherwise you'd be losing too much heat between slaps. And even in a vacuum, you'd lose some heat via radiation... So really, you should stick a temperature probe in there and just keep slapping until it reaches 165°F. Don't even bother counting.

Sorry for the silly units, I only know food safety temperatures off the top of my head in °F.