Calculating PE and Initial Speed for Colliding Alpha Particles

In summary, "PE from point charges" refers to the potential energy resulting from the interaction of charged particles at specific points in space. This energy is calculated using the equation PE = (k * q1 * q2) / r, where k is the Coulomb constant, q1 and q2 are the charges of the particles, and r is the distance between them. The potential energy can be negative, indicating a repulsive force between the particles, or positive, indicating an attractive force. The distance between point charges is inversely proportional to the potential energy, meaning that as the distance increases, the potential energy decreases. Real-life applications of potential energy from point charges include electronic devices, batteries, and lightning and thunderstorms.
  • #1
pulser45
3
0
I need help for the following problem:

Two alpha-particles (diameter 1.9 x 10^-19 m) are headed directly toward each other with equal speeds. Compute the minimum energy in electron volts each particle must have if they are to collide. What inital speed must each particle have?

For the initial speed, i know that i need the work energy theorem. However, i don't know how to get the work. Thanks.
 
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  • #2
Find the potential energy when the particles are touching each other.
Then find what their speeds would be far away from each other if they were released from this condition.
 
  • #3


To calculate the minimum energy in electron volts (eV) for each alpha particle, we can use the equation PE = 1/2mv^2, where PE is the potential energy, m is the mass of the alpha particle, and v is the initial speed.

Since the two alpha particles have equal speeds, we can use the same formula for both particles. The mass of an alpha particle is approximately 6.64 x 10^-27 kg. Plugging in this value and the given diameter (1.9 x 10^-19 m) into the formula, we get:

PE = 1/2(6.64 x 10^-27 kg)(v^2)

To find the minimum energy in eV, we need to convert the units of mass and velocity into eV. We can use the conversion 1 eV = 1.602 x 10^-19 J. Therefore, the equation becomes:

PE = 1/2(6.64 x 10^-27 kg)(v^2)(1.602 x 10^-19 J/eV)

Simplifying, we get:

PE = 5.33 x 10^-46 v^2 eV

To solve for the initial speed, we can use the work-energy theorem, which states that the change in kinetic energy (KE) is equal to the work done on an object. In this case, the work done is the change in potential energy (PE) since the alpha particles are initially at rest.

Therefore, we can set the initial PE to be equal to the final KE:

PE = KE

Substituting the formula for PE that we found earlier, we get:

5.33 x 10^-46 v^2 eV = 1/2mv^2

Solving for v, we get:

v = √(5.33 x 10^-46 eV/m)

Converting the units back to m/s, we get:

v = 1.30 x 10^7 m/s

Therefore, each alpha particle must have a minimum energy of 5.33 x 10^-46 eV and an initial speed of 1.30 x 10^7 m/s in order to collide. I hope this helps with your problem!
 

1. What is the definition of "PE from point charges"?

"PE from point charges" refers to the potential energy that results from the interaction between two or more charged particles at specific points in space.

2. How is the potential energy calculated for point charges?

The potential energy for point charges is calculated using the equation PE = (k * q1 * q2) / r, where k is the Coulomb constant, q1 and q2 are the charges of the particles, and r is the distance between them.

3. Can the potential energy of point charges be negative?

Yes, the potential energy of point charges can be negative. This indicates that the particles have a repulsive force between them, as opposed to a positive potential energy which indicates an attractive force.

4. How does the distance between point charges affect the potential energy?

The potential energy between point charges is inversely proportional to the distance between them. This means that as the distance increases, the potential energy decreases and vice versa.

5. What are some real-life applications of potential energy from point charges?

Some examples of real-life applications of potential energy from point charges include the operation of electronic devices, the function of batteries, and the behavior of lightning and thunderstorms.

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