PLEASE HELP IM BEING TIMED A tortoise and a hare raced and the following number were recorded: The tortoise "ran" the entire 100 meter race at a steady pace of 0.2 m/s. The hare started from rest and accelerated at a constant rate of 0.4m/s^2 for the first 30 meters, then rested for 6 minutes, then finished the last 70 meters of the race at a steady speed of 0.5 m/s. How much time (in seconds) did the hare take to complete the race?

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.