(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

In the neck of the picture tube of a certain black-and-white television set, an electron gun contains two charged metallic plates 2.80cm apart. An electric force accelerates each electron in the beam from rest to 9.60% of the speed of light over this distance. a) determine the kinetic energy of the electron as it leaves the electron gun. Electrons carry this energy to a phosphorescent material on the inner surface of the television screen material making it glow. For an electron passing between the plates in the electron gun, determine b) the magnitude of the constant electric force acting on the electron, c) the acceleration, and d) the time of flight.

Electron mass = 9.10938188 * 10^-31 kg

C = 299792458 m/s

Electron velocity = 28780075.968 m/s (.0960 * C)

Distance between plates = .028m

2. Relevant equations

KE = 1/2m* v^2

F= mass * acceleration

3. The attempt at a solution

a) KE = 1/2m * v^2

= 1/2(9.10938188*10^-31kg) * ( 28780075.968m/s)

= 3.77261759 * 10^-16 Joules

b) F=m*a

= (9.10938188*10^-31kg) * [ (28780075.968m/s)^2 / (.028m) ]

= 2.694722685 * 10^-14 N

c) a = F/m

= 2.694722685*10^-14N / 9.10938188*10^-31kg

= 2.9581839*10-46 m/s^2

d) ???

and Im not sure if my parts b and c are correct

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Work-Kinetic Energy Theorem

**Physics Forums | Science Articles, Homework Help, Discussion**