A charge of #3 C# is at the origin. How much energy would be applied to or released from a # -1 C# charge if it is moved from # ( 2 , -8 ) # to #(-2 , 5 ) #?

1 Answer
Mar 14, 2016

Answer:

#W~=-8,37*10^9 J#

Explanation:

#P_1(2,-8)" "P_2=(-2,5)#
#r_1=sqrt((2-0)^2+(-8-0)^2)=sqrt(4+64)=sqrt68#
#"(distance between origin and the point of " P_1)#

#r_2=sqrt((-2-0)^2+(5-0)^2)=sqrt(4+25)=sqrt29#
#"(distance between origin and the point of " P_2)#

#E=k (q_1*q_2)/r_1+k(q_1*q_2)/r_2" (1)"#
#"it is done work; if a charge is moved from one point to another."#
#"Work doing by system is equal the potential energy of system."#
#"We obtain the fallowing equation; if we rearrange the equation (1)" #
#W=k.q_1*q_2(1/r_1+1/r_2)#
#W=k*3*(-1)(1/sqrt68+1/sqrt29)#
#W=-3k((sqrt29+sqrt68)/(sqrt(68*29))) " "k=9.10^9#
#W=-27*10^9*0,31#
#W~=-8,37*10^9 J#
#"The energy of system has decreased"#