6. Two positive charges, each with 6.0 x 10^-6 C, are 0.75 meters apart.
What force exists between the two charges?

F = 5.76x10^-1 N

Explanation:

The force between two charges is:

F = k*q1*q2/r^2

where k = 9x10^9 N*m^2/C^2 is the Coulomb's constant.

q1 and q2 = 6x10^-6 C

and r is the distance between the charges, here r = 0.75m

then the force is:

F = ( 9x10^9 N*m^2/C^2)*6x10^-6 C*6x10^-6 C/(0.75m)^2 = 576x10^-3 N

F = 5.76x10^-1 N

We have a positive force, this means that we have a repulsive force.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

15.3 cos 65 degrees trig