Two stationary point charges +3 nC and + 2nC are separated bya distance of 50cm

Anish Buchanan

Anish Buchanan

Answered question

2021-03-29

Two stationary point charges +3nC and +2nC are separated bya distance of 50cm. An electron is released from rest at a pointmidway between the two charges and moves along the line connectingthe two charges. What is the speed of the electron when it is 10cm from +3nC charge?
Besides the hints I'd like to ask you to give me numericalsolution so I can verify my answer later on. It would be nice ifyou could write it out, but a numerical anser would be fine alongwith the hint how to get there.

Answer & Explanation

Luvottoq

Luvottoq

Skilled2021-03-31Added 95 answers

image
We can see from the diagram that the motion is along the x-axis.
xi=25cm,xf=10cm
Consider xi=0 and the positve x-axis toward the 3nC charge, so xf=15cm.
xfxi=15cm
F at this point equal to
F=Fby3nC+Fby2nC
Fby3nC=k3×1061.6×101910×102
Fby2nC=k(2×1061.6×1019}{40}×102
Caculate both forces and then ,
ax=Fmelectron
Using constant acceleration motion equations, you can obtain the velocity when you have the acceleration.
Use :
vx=2ax(xfξ)
Assuming that the motion began at the origin, you know that the initial velocity is zero 
and (xfxi)=15cm

Eliza Beth13

Eliza Beth13

Skilled2023-05-19Added 130 answers

Given:
Charge 1, Q1 = +3nC
Charge 2, Q2 = +2nC
Distance between the charges, d = 50 cm
Distance of the electron from the +3nC charge, x = 10 cm
The potential energy of the electron at the midpoint is given by the equation:
PEinitial=k·|Q1·Q2|d
where k is the electrostatic constant, which is approximately 8.99×109Nm2/C2.
The final kinetic energy of the electron when it is 10 cm from the +3nC charge is given by:
KEfinal=12·m·v2
where m is the mass of the electron, which is approximately 9.11×1031 kg, and v is the speed of the electron.
Since energy is conserved, we can equate the initial potential energy to the final kinetic energy:
k·|Q1·Q2|d=12·m·v2
Now we can plug in the given values:
k=8.99×109Nm2/C2
Q1=+3×109 C
Q2=+2×109 C
d=50 cm
m=9.11×1031 kg
x=10 cm
Substituting these values into the equation, we can solve for v:
(8.99×109Nm2/C2)·|(3×109C)·(2×109C)|(50×102m)=12·(9.11×1031kg)·v2
Simplifying the equation:
8.99×3×2×101850×102=12·9.11×v2
1.0788×1015=4.5555×1031·v2
Now, solve for v:
v2=1.0788×10154.5555×1031
v2=2.3663×1015
v=2.3663×1015
v4.865×107 m/s
Therefore, the speed of the electron when it is 10 cm from the +3nC charge is approximately 4.865×107 m/s.
madeleinejames20

madeleinejames20

Skilled2023-05-19Added 165 answers

Answer:
7.89×1017 m/s
Explanation:
Let's denote the charge of the electron as e and the distance between the charges as d. The given values are:
Charge of +3nC charge (Q1) = +3nC = 3×109 C
Charge of +2nC charge (Q2) = +2nC = 2×109 C
Distance between the charges (d) = 50 cm = 0.5 m
Distance from the +3nC charge to the electron (r) = 10 cm = 0.1 m
The electric potential energy (PE) of the electron at the midpoint is given by:
PE=Q1·Qe4πϵ0·d/2+Q2·Qe4πϵ0·d/2
where Qe is the charge of the electron and ϵ0 is the permittivity of free space.
The initial potential energy (PEi) of the electron at the midpoint is:
PEi=Q1·Qe4πϵ0·d/2+Q2·Qe4πϵ0·d/2
The final kinetic energy (KEf) of the electron when it is 10 cm away from the +3nC charge is:
KEf=12m·v2
where m is the mass of the electron and v is its velocity.
Since the electron is released from rest, its initial kinetic energy (KEi) is zero.
By the conservation of energy principle, we have:
PEi=KEf
Substituting the values into the equation and solving for v:
Q1·Qe4πϵ0·d/2+Q2·Qe4πϵ0·d/2=12m·v2
Now we can substitute the known values:
(3×109C)·(1.6×1019C)4πϵ0·(0.5/2)m+(2×109C)·(1.6×1019C)4πϵ0·(0.5/2)m=12(9.1×1031kg)·v2
Simplifying the equation and solving for v:
5.4×1062.56×106=4.55×1031·v2
2.84×106=4.55×1031·v2
v2=2.84×1064.55×1031
v=2.84×1064.55×1031
v=6.24×1036
v7.89×1017 m/s
Therefore, the speed of the electron when it is 10 cm away from the +3nC charge is approximately 7.89×1017 m/s.
Mr Solver

Mr Solver

Skilled2023-05-19Added 147 answers

Step 1:
The electric potential energy between two point charges can be calculated using the formula:
U=k·q1·q2r,
where U is the electric potential energy, k is the electrostatic constant (9×109N·m2/C2), q1 and q2 are the charges, and r is the distance between the charges.
At the midpoint between the two charges, the electric potential energy of the electron is zero since it is equidistant from both charges.
As the electron moves towards the +3nC charge, it gains potential energy. At a distance of 10cm from the +3nC charge, the potential energy gained by the electron can be calculated using the formula mentioned above. This potential energy will be converted into kinetic energy, given by the equation:
K=12mv2,
where K is the kinetic energy, m is the mass of the electron (9.11×1031kg), and v is the velocity (speed) of the electron.
Since the total mechanical energy (the sum of kinetic and potential energies) is conserved, we can equate the potential energy gained by the electron to its kinetic energy at a distance of 10cm from the +3nC charge:
k·q1·qelectronr=12mv2,
where qelectron represents the charge of the electron (-1.6nC).
Step 2:
Now we can solve this equation for v, the velocity (speed) of the electron.
Remember to substitute the appropriate values for k, q1, qelectron, r, and m before solving the equation.
(9×109N·m2/C2)·(3×109C)·(1.6×109C)0.1m=12·(9.11×1031kg)·v2
Now, we can solve for v:
5.4×105N·m=(4.5555×1031kg)·v2
Dividing both sides by (4.5555×1031kg):
v2=5.4×105N·m4.5555×1031kg
v21.184×106m2/s2
Taking the square root of both sides:
v1.088×103m/s
Therefore, the speed of the electron when it is 10cm from the +3nC charge is approximately 1.088×103m/s.

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