1 A see-saw is supported at the center. A 40kg boy sits at the left, 4 m away from the center, and a girl sits 5 m to the right of the center. The see-saw is balanced. What is
the mass of the girl?

k2s for potassium sulphide

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

365.25 earth days are in the year of a light year