old speed/trajectory problem

[HeLLz aNgeL]

http://www.physicsforums.com/showthread.php?t=62644

can anyone figure out how to do this ? because the sole reply that the thread got, doesnt seem to work for me..

thanks !

[Astronuc]

What is not working?

The attachment reads -

\vec{r} = A (1 m/s)t\hat{x}\,+\,A[(1 m/s^3)t^3-6(1 m/s^2)t^2]\hat{y}

[HeLLz aNgeL]

yes, but i cant seem to solve the questions it asks :P

[HeLLz aNgeL]

bump ... help please !

[learningphysics]

bump ... help please !

Did you take the derivative of \vec{r}(t) to get \vec{v}(t)? What did you get?