As Yoda dueled Count Dooku on Geonosis, Dooku used the Force to drop a silo onto Obi-wan Kenobi and Anakin Skywalker. Yoda stops the silo from hitting the two Jedi, and that gives Dooku more than enough time to run into his escape ship and leave.
The moment is from 4:19 through 4:41 in this video clip.
Yoda holds the silo in place for several seconds before moving it out of the way. He could have used that moment to shove the silo right up entry way of Dooku's spacecraft to prevent him from escaping.
We have seen Yoda move heavy objects with the Force very quickly on short notice. He could have destroyed the escape craft easily.
So why did Yoda let Dooku escape?