Question

two identical positive charges are fixed on the y-axis at equal distance from the origin O .A particle with a negative charge start on the x axis at a large distance from O, moves along the x-axis, passes through O, and moves far away from O on the side.Its acceleration a is taken as positive along its direction of motion. Plot acceleration a of the particle against its x-coordinate​

Answer 1

Answer:

Write any thing you know

Answer 2

Answer:

Consider the attached free body diagram for the given scenario.

From coulomb's law,

∣F

1

∣=∣F

2

∣=

4πε

o

r

2

qQ

In y-direction, forces cancel, F

y

=0

In x-direction, forces add up. Also, it is directed in +ve x direction if the position of −q is along −ve x axis and in −ve x direction if the position of −q is along +ve x axis.

Hence,

F

x

=

4πε

o

r

2

2qQcosθ

i

^

∀ x<0

F

x

=−

4πε

o

r

2

2qQcosθ

i

^

∀ x≥0

But cosθ=

r

x

r=

x

2

+d

2

Substituting in force equation, we get

F

x

=

4πε

o

(x

2

+d

2

)

3/2

2qQx

i

^

∀ x<0

F

x

=−

4πε

o

(x

2

+d

2

)

3/2

2qQx

i

^

∀ x≥0

Now, a=

m

F

by Newton's second law. It is positive when x is negative and negative when x is positive. This is satisfied only in option (C).