A point charge q1=+2.40μC is held stationary at the origin. A second point charge q2=−4.30μC moves from the point x=0.125m , y=0, to the point x=0.275m , y=0.275m.

Part A

What is the change in potential energy of the pair of charges?

Express your answer in joules to three significant figures.

Part B

How much work is done by the electric force on q2?

Express your answer in joules to three significant figures.

Explanation:

Potential energy of a pair of charges

= k q₁q₂ /r₁₂

At r₁₂ = .125 m

= - 9 x 10⁹ x 2.4 x 4.3 x 10⁻¹² / .125

= - 743 x 10⁻³J

At r₁₂ = √2 x .275 m

- 9 x 10⁹ x 2.4 x 4.3 x 10⁻¹² / √2 x .275

= - 238.85  x 10⁻³J

= 239 x 10⁻³ J

Change = - 238.85  x 10⁻³ +743 x 10⁻³

= 504.15 x 10⁻³ J

B )

Work done by electric force will be same but in negative sign

= - 504.15 x 10⁻³ J

= - 504 x 10⁻³ J

he made 11 calls in one day

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force