A karate student trying to break bricks in half is wondering if it would be more effective to strike these bricks and stop her hand at the top surface of the blocks, or to let her hand bounce after she strikes. How would you advise her, using physics?
Stop hand or bound?
Why?

stop your hand so it doesn't hurt as much and if u stop your hand it would make more of an impact because if your hand bounces it means not enough strength so she should stop her hand

hujjujddf

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.