Particle Kinetic energy problem

AI Thread Summary
The discussion centers on calculating the kinetic energy of particle B when two charged particles are released from rest and move apart due to their repulsive Coulombic force. The user expresses confusion about applying conservation of energy and determining the final kinetic energy without knowing particle A's velocity. Suggestions include identifying the forces acting on the particles, applying Newton's second law, and solving for their velocities over time. The importance of focusing on the Coulombic force while neglecting gravity is emphasized. The user remains uncertain about the direction of the forces and the correct setup for the equations.
Punchlinegirl
Messages
221
Reaction score
0
Particles A (of mass m and charge Q) and B (of mass m and charge 5Q) are released from rest with the distance between them equal to 0.9773 m. If Q = 8 \mu C, what is the kinetic energy of particle B at the instant when the particles are 2.9773 m apart? Answer in units of J.
I really don't know how to do this problem. I tried to set it up by using conservation of energy.
KE_A + KE_B + U_A + U_B = KE_A + KE_B + U_A + U_B
qkQ/.9773 + qk5Q/.9773 = KE_A + KE_B + qkQ/2.9773 + qk5Q/2.9773.
I really don't think this setup is right, and I have no idea how I would be able to solve for the final kinetic energy of B when I don't know the final velocity of A.
Suggestions?
 
Physics news on Phys.org
1)Start out with determining what force is acting between those particles. Also, make sure that you have the correct direction of the force vector with respect to an X and Y axis.

2)Apply Newton's second Law in both the X and Y direction.

3) Solve the equations to get the particles' velocity and positions as a function of time

marlon
 
Since the particles both have a positive charge, I know they will repel. Aside from that force, the normal force and gravity, those are the only forces I know of. Is that right?
 
Coulombic force and gravity, yes.

Though in this problem, i think you can omit gravity.

marlon
 
Wouldn't the columbic force just be in the x-dir? So it would be like
qE_b- qE_a= ma ?
Sorry... I'm still confused.
 

Thread 'Rolling without slipping on a curved surface'

Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
View full post »
Thread 'Voltmeter readings for this circuit with switches'

Thread 'Voltmeter readings for this circuit with switches'

TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
View full post »
Thread 'Trying to understand the logic behind adding vectors with an angle between them'

Thread 'Trying to understand the logic behind adding vectors with an angle between them'

My initial calculation was to subtract V1 from V2 to show that from the perspective of the second aircraft the first one is -300km/h. So i checked with ChatGPT and it said I cant just subtract them because I have an angle between them. So I dont understand the reasoning of it. Like why should a velocity be dependent on an angle? I was thinking about how it would look like if the planes where parallel to each other, and then how it look like if one is turning away and I dont see it. Since...
View full post »

Similar threads

Problem related to a parallel plate capacitor
Replies
15
Views
2K
A block dropping onto a spring system
2
Replies
58
Views
2K
Kinetic Energy of a Cylinder Rolling Without Slipping
Replies
21
Views
4K
Kinetic Energy of a Charged Particle near a Charged Ring
Replies
2
Views
1K
Conservation of Momentum Problem - Mechanical and Kinetic Energies
Replies
2
Views
974
Kinetic energy transformed in a collision involving coalescing particles
Replies
9
Views
1K
Work done during a collision -- Change in Kinetic Energy & change in Momentum
Replies
1
Views
2K
Confused about a conservation of energy problem
Replies
4
Views
2K
Speed of two charged particles repelling each other
Replies
7
Views
3K
Why Does Kinetic Energy Change After Collision in EENGA 2019 Question?
Replies
3
Views
1K

Hot Threads

Recent Insights

Back
Top