To a Ground-Based Observer, What Is the Speed of a Moving

Question 12
Multiple Choice

To a ground-based observer, what is the speed of a moving ball tossed backward at 30 km/hour on a train moving forward at 90 km/hr? A) 150 km/hr B) 60 km/hr C) 30 km/hr D) 90 km/hr E) 2700 km/hr