Pressure on the inside of the balloon was greater than the pressure on the outside of the balloon so it pushed out until the pressures equalized.
I believe that #1 is the lie, but I'm not great at this subject.
Negative force
The woman is applying force to stop the child or to prevent him from running.
I hope this helps...
Explanation:
solid: table, biscuit
liquid: water, urine
gas: oxygen, carbon dioxide