Batgirl

Barbara "Babs" Gordon, also known as Batgirl. She assembles the series' superhero team in the first episode, Sweet Justice, after moving to Metropolis from Gotham with her father Mr Gordon.

Physics
Babs tells Mr Wilson in the episode Dinner for Five that she likes physics and gym class best. She devises a method of time travel in the episode Back in a Flash. When she faces the decision of having to undo the changes she made in time, Barry tells her that she's his best friend and whatever choice she'll make, he'll support her.