Johanna

1. Topluluk
2. General Khan Academy Questions
3. Mastery In a Course

Yes, you can get to 100 percent mastery in a course without doing the course challenge. As you suggest, it depends on if you mastered the skills or not. To achieve mastery in those skills, though, ...

1. Topluluk
2. Study Group
3. Re acceleration formula

Both of those equations are very widely accepted as correct. What do you mean by “the v0t is not half”/ why would that make one equation wrong? Sorry about the late response.

1. Topluluk
2. Study Group
3. Chemistry of life - carbon-14 dating question

If you want, you might have better luck getting an answer if you ask this in the questions section under that article.