Suppose you were to fill a balloon with air then let go of it withoutntying it closed. What causes the balloon to fly away?

When a balloon is inflated, the pressure inside the ballon is greater than the pressure outside the balloon. When let go of (or when the balloon is open), the air is released as there is no long a difference in pressure between outside the balloon and inside the balloon. This results in a force in the opposite direction due to the escaping air that provides the force, which causes it to fly away!

Hope this helps :)

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.