Calculating Exercise: Get Expert Help Here!

[Poriya]

Homework Statement

"Calculate the finial velocity of two electrons that
start at a distance of 1 nm and have travelled
infinite distances. Use the law of conservation of
energy.
Try also to approximate the motion by
considering single small time steps within which
the force and hence the acceleration can be
considered constant."

Relevant Equations

PE = mgh
KE= 1/2 M v^2

Hello everybody is anyone here who knows how I can calculate this exercise?

 

[etotheipi]

What is the initial energy of the system? What is the final energy of the system?

 

[DaveE]

You're equations have left out one of the most significant properties of the electron. It's the property I think of first for this particle.

 

[berkeman]

Welcome to the PF.

Relevant Equations:: PE = mgh

That equation is for the potential energy due to a gravitational field, but it sounds like this problem is for two electrons repelling each other in free space due to electrical forces, no? What equations can you list for potential energy due to an electric field? What is the repulsive force between two electrons, based on their separation distance?

 

[Poriya]

What is the initial energy of the system? What is the final energy of the system?

Is not given

 

[Poriya]

Welcome to the PF.

That equation is for the potential energy due to a gravitational field, but it sounds like this problem is for two electrons repelling each other in free space due to electrical forces, no? What equations can you list for potential energy due to an electric field? What is the repulsive force between two electrons, based on their separation distance?

My problem is that I can't follow what my professor is asking for? I think there are some Information missing...

 

[etotheipi]

My problem is that I can't follow what my professor is asking for? I think there are some Information missing...

You hold the two electrons close to each other, then let go and they accelerate away from each other. You can equate the total energy of the system at the start to that when they are separated at infinity with unknown kinetic energy.

Granted, you do need to know the potential energy of a system of two charges. Have you come across this?

 

[Poriya]

You hold the two electrons close to each other, then let go and they accelerate away from each other. You can equate the total energy of the system at the start to that when they are separated at infinity with unknown kinetic energy.

Granted, you do need to know the potential energy of a system of two charges. Have you come across this?

Do I need to know the acceleration and plug it into the equation or is that not necessary to solve the question?

 

[haruspex]

Do I need to know the acceleration and plug it into the equation or is that not necessary to solve the question?

No, don't consider acceleration. Just try to answer the questions @etotheipi asked in post #2. There is enough information to answer these.
What two forms of energy are involved here? What is the initial value of each? What is the final value of each? What equation can you write?
One of these four energies will involve the unknown you are asked to find.

 

[Poriya]

No, don't consider acceleration. Just try to answer the questions @etotheipi asked in post #2. There is enough information to answer these.
What two forms of energy are involved here? What is the initial value of each? What is the final value of each? What equation can you write?
One of these four energies will involve the unknown you are asked to find.

I will try thanks