4. 2D Kinematics

Sam is driving down the road at $30\mathrm{m}/\mathrm{s}$. Toni, who is in front of Sam, is driving $25\mathrm{m}/\mathrm{s}$ in the same direction. Toni, watching in her rear-view mirror, sees Sam reach out the window and throw a ball towards her. If Sam sees the ball moving away from him at $10\mathrm{m}/\mathrm{s}$, does Toni see the ball moving towards her, or away from her? How fast is the ball moving according to Toni?

On still water, Olive can paddle her kayak $5\mathrm{m}/\mathrm{s}$. She wishes to cross a river which flows east at $2\mathrm{m}/\mathrm{s}$. If Olive is standing on the south bank, and would like to reach a point directly across the river on the north bank, at what angle upstream (west of north) should she point her Kayak?