A train is going directly South at 60 mph. An action-movie star is atop the train, running North at 6 mph. Relative to someone standing on the ground, how fast is the action-movie star moving, and in what direction? North is positive and South is negative.
Use SI units in your answer.
V=6-60=-54 Mi/h = -54Mi/h * 1600m/Mi *
1h/3600s = -24 m/s = 24 m/s Due South.