A bar which is initially at rest is allowed to move along frictionless rails as shown. Due to an applied X XXXX potential difference, electrons move down the bar as indicated in the diagram. The bar is then X X influenced by the external magnetic field shown X X here . X XXXXXXXX XXXXXXX V 15. What is the direction of the magnetic force on X the bar? Explain. X X XXX 16. Will that force change in magnitude or direction as time passes? Explain why or why not. 17. Describe how the velocity of the bar (magnitude and direction) changes as time passes. Explain. 18. Describe as accurately as possible the future motion of the bar