Does jQuery slow your web app? By how much? Is it worth it?

Does jQuery slow your web app? By how much? Is it worth it?

Hi All,

Simple, but important question. I'm starting a web application that is intended to be used by business owners. I know that jQuery adds amazing effects (I am using only a couple), but I want to know by how much is the application affected by? And is it worth the effect on the application performance?

Thanks,
all4peace