You can use Newton's Second Law which states:

Plug in given information:

This is closest to option
b which is your answer.
Complete Question
The complete question is shown on the first uploaded image
Answer:
The electric field at that point is
Explanation:
From the question we are told that
The radius of the inner circle is 
The radius of the outer circle is 
The charge on the spherical shell
The magnitude of the point charge at the center is 
The position we are considering is x = 0.60 m from the center
Generally the electric field at the distance x = 0.60 m from the center is mathematically represented as

substituting values

where k is the coulomb constant with value 
substituting values


Answer:

Explanation:
As per mechanical energy conservation we can say that here since friction is present in the barrel so we will have
Work done by friction force = Loss in mechanical energy
so we will have

here we know that



Initial compression in the spring is given as



now from above equation




You put electricity<span> into it at one end and an </span>axle<span> (metal rod) rotates at the other end giving you the power to drive a machine of some kind.
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A sphere is charged with electrons to −9 × 10−6 C. The value given is the total charge of all the electrons present in the sphere. To calculate the number of electrons in the sphere, we divide the the total charge with the charge of one electron.
N = 9 × 10−6 C / 1.6 × 10−19 C
N = 5.6 x 10^13