A proton is released from rest at the origin in a uniform electric field in the positive x direction with magnitude 850 N/C. What is the change in the electric potential energy of the proton–field system when the proton travels to x=2.50 m?

A.3.40 X 10^-16 J
B.-3.40 X 10^-16 J
C.2.50 X 10^-16 J
D.-1.60 X 10^-19 J
E.-2.50 X 10^-16 J

Aheavy boy and a lightweight girl are balanced on a massless seesaw. the boy moves backward, increasing his distance from the pivot point. what happens to the seesaw? it is impossible to predict without knowing additional information. the side the boy is sitting on will tilt downward. the side the girl is sitting on will tilt downward. nothing; the seesaw will remain balanced.