A balloon is rubbed against a student's hair and then touched to a wall. The balloon sticks to the wall due to:
(a) magnetic forces between the particles of the balloon and the
particles of the wall
(b) electrostatic forces between the particles of the balloon and
the particles of the wall
(c) magnetic forces between the particles of the wall
(d) electrostatic forces between the particles of the balloon

b

Explanation:

electrostatic forces btw the particles of the balloon and the particles of the wall

B. electrostatic forces between the particles of the balloon and the particles of the wall

B

answer: the potential energy decreases from 379 j to 243 j

explanation:

for the law of conservation of energy, the total energy in a system must be conserved. the total energy of the system is given by the sum of kinetic (k) and potential (u) energy:

e = k + u

the total energy is e=675 j, and this does not change.

initially, the kinetic energy is k=296 j, so the potential energy is

at the end, the kinetic energy is k=432 j, so the potential energy is

so, we see that the potential energy has decreased from 379 j to 243 j.