Company Physics Classroom, LLC created these great apps:
Minds On Physics - Part 1, Minds On Physics - Part 2, Minds On Physics - Part 3, Minds On Physics - Part 4, Minds On Physics - Part 5, Minds On Physics - Part 6, MOP Part 1, MOP Part 2, MOP Part 6, MOP Part 4, MOP Part 5, MOP Part 3, and others..