A ball is launched from a 75 meter tower and lands 20 meters away. What was the initial horizontal velocity of the ball? 5.01 m/s
4.22 m/s
3.91 m/s
5.13 m/s

Along wire carrying a 4.2 a current perpendicular to the xy-plane intersects the x-axis at x=−1.7cm. a second, parallel wire carrying a 3.0 a current intersects the x-axis at x=+1.7cm. part a at what point on the x-axis is the magnetic field zero if the two currents are in the same direction? express your answer to two significant figures and include the appropriate units.