A small sphere with positive charge q and mass m is releasedfrom rest in a uniform electric field E that is directed vertically upward.The magnitude of the field is large enough for the sphere to travelupward when it is released. How long does it take the sphere to travel upwarda distance d after being released from rest? Give your answer in termsof q, m, d, E, and the acceleration due to gravity, g.

Problem 12:   A simple and common technique for accelerating electrons is shown in the figure, which depicts a uniform electric field between two plates. Electrons are released, usually from a hot filament, near the negative plate, and there is a small hole in the positive plate that allows the electrons to pass through. E = 2.4 × 104 N/C Calculate the horizontal component of the electron's acceleration if the field strength is 2.4 × 104 N/C. Express your answer in meters per second squared, and assume the electric field is pointing in the negative x-direction as shown in the figure.

A thin metal ring of radius R is placed horizontally and charged with charge Q. A point like object with mass m and charge q is let fall vertically from a height H measured from the plane of the ring. The initial velocity is zero. The object is falling along the axis of a ring. What is the velocity of the object, when it reaches the middle of the ring? Gravitational acceleration is denoted by g.

A uniform electric field exists in a region between two oppositely charged plates. An electron is released from rest at the surface of the negatively charged plate and strikes the surface of the opposite plate, 2.0 cm away, in a time 1.5 X 10-8 s. (a) What is the speed of the electron as it strikes the second plate? (b) What is he magnitude of the electric field Ē?