According to the meaning of the question, we can know that two balloons have the same charge, and the same charge repels each other; They all change from rest to motion under the action of force, which shows that force can change the motion state of objects.

So the answer is: like charges repel each other, and force can change the motion state of an object.

principle

The amount of charge is called the amount of charge, that is, the amount of charge carried by a substance, atom or electron. The sign of the charge is Q, and the unit is C (Coulomb).

We often refer to "charged particles" as charges. In addition, according to the directionality of electric field, charges can be divided into positive and negative charges, and electrons are negatively charged.

Positive charge: specify the positive charge of glass rod wiping ribbon.

Negative charge: it is stipulated that the rubber rod rubs the fur with negative charge.