The function in part (c) of this activity is in fact a scalar function (it's the result of a dot product). I am thus renaming it r(t) instead of \vr(t) so it looks like a scalar function.
Spencer, I updated this to be f(t) to differentiate in name as well as notation from the vector valued functions. I have changed this manually in the 2025 Edition as well. Thanks.
The function in part (c) of this activity is in fact a scalar function (it's the result of a dot product). I am thus renaming it r(t) instead of \vr(t) so it looks like a scalar function.