Ted travels in a railroad car at constant velocity while his motion is watched by Alice, who is at rest on the ground (Fig. P27.1). Ted’s speed v is much less than the speed of light. Ted releases a ball from his hand and observes that in his reference frame the ball falls directly downward. Hence, according to Ted, the component of the ball’s velocity along the horizontal direction is zero. 

(a) According to Alice, what is the ball’s velocity along x just after the ball is released? 

(b) According to Alice, what is the ball’s velocity along x just before the ball lands at Ted’s feet? 

(c) According to Alice, what is the acceleration of the ball along x? 

(d) According to Ted, what is the acceleration of the ball along x? 

(e) What is the force F_x on the ball along x? Do Ted and Alice agree on the value of F_x? Explain how this answer is expected from the principle of Galilean relativity.