Two small spheres spaced 20.0 cm apart have equal charge. how many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 4.57 x 10-21 n?
a. 562
b. 9.14 * 10^3
c. 1.01 * 10^6
d. 891

explanation:

the masses of the objects and the distance between them

i think it's 35 meters

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min

electrical potential energy =0.072 j

explanation:

electrical potential energy is given by

u= q δv

q= charge=6 c

δv= potential difference and is given by

δv= e d

e= electric field

d= distance=5 mm=0.005 m

δv=2.4 (0.005)=0.012 v

now electric potential energy= u= q δv

u=6 (0.012)

u=0.072 j