What is the final speed of a proton in an electric field after traveling 2.0 mm?

In summary, a proton with a speed of 2.1*10^4 m/s moves in a uniform electric field with a magnitude of 2.3*10^3 N/C. To find the final speed after moving a distance of 2.0 mm, one must use the work-energy theorem or calculate the electrostatic potential energy lost. The mass and charge of the proton are needed to accurately solve the problem.
  • #1
spoonthrower
37
0
A uniform electric field has a magnitude of 2.3*10^3 N/C. In a vacuum, a proton begins with a speed of 2.1*10^4 m/s and moves in the direction of this field. Find the speed of the proton after it has moved a distance of 2.0 mm please help. Thanks.
 
Physics news on Phys.org
  • #2
What are your thoughts on it?
 
  • #3
i know F=qE, so is there a value of q for a proton that i don't know about. once i know the force i guess i need to find the acceleration to calculate the final speed. so i would need the mass of a proton?
 
  • #4
Yeah, you need the mass and charge of the proton (which you can look up anywhere). So now you know F (which is constant) and it's just a classical mechanics exercise, analogous to a particle in a uniform gravitational field.

It is more efficient to use an energy approach though. The potential energy lost in moving the 2mm is gained by the kinetic energy of the proton.
 
  • #5
so I would use .5mvf^2-.5mvo^2=mgh

The mass cancels i know that. I use gravity?

I am still getting the wrong answer
 
  • #6
spoonthrower said:
so I would use .5mvf^2-.5mvo^2=mgh

The mass cancels i know that. I use gravity?
No! The only thing analogous is that the force acting on the particle is constant. You mustn't use gravitational potential energy (which is proportional to the mass) but electrostatic potential energy (Which is proportional to the charge). I made the analogy to simplify the view on the problem, but I see it's only confusing. Forget I said the whole thing!

If you don't know electrostatic potential energy, just use the work-energy theorem. What is the work done by the field in moving the particle those 2mm?
 
Last edited:

What is an electric field?

An electric field is a physical quantity that describes the influence that a charged particle has on other charged particles in its surroundings. It is represented by a vector that shows the direction and magnitude of the force exerted on a test charge placed in the field.

How do you calculate the electric field?

The electric field can be calculated by dividing the force exerted on a test charge by the magnitude of the test charge. Mathematically, it is represented by the equation E = F/q, where E is the electric field, F is the force, and q is the test charge.

What factors affect the strength of an electric field?

The strength of an electric field is affected by the magnitude of the source charge, the distance from the source charge, and the medium in which the field exists. The electric field strength decreases as the distance from the source charge increases and can be stronger or weaker depending on the properties of the medium.

What is the difference between electric potential and electric field?

Electric potential is a scalar quantity that represents the electrical potential energy per unit charge at a specific point in space. It is closely related to the electric field, which is a vector quantity that describes the force experienced by a charged particle at a specific point in space. The electric field is the gradient of the electric potential, meaning it is the change in electric potential over a given distance.

How can electric field problems be solved?

Electric field problems can be solved using mathematical equations and principles, such as Coulomb's law and the principle of superposition. By understanding the properties of electric fields and using these equations, scientists can calculate the strength and direction of electric fields in various scenarios and solve problems related to them.

Similar threads

  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
12
Views
2K
  • Introductory Physics Homework Help
Replies
9
Views
7K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
947
  • Introductory Physics Homework Help
Replies
4
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
14
Views
4K
Back
Top