How to find initial velocity from position vs time graph

A-4.60 μc charge is moving at a constant speed of 6.80×105 m/s in the +x−direction relative to a reference frame. at the instant when the point charge is at the origin, what is the magnetic-field vector it produces at the following points.

In a system, when potential energy decreases, then entropy also decreases. true false

Which notation is used to represent an alpha particle? a. b. c. d.