A 0.07 kg bullet traveling at speed hits a 13.6 kg block of wood and stays in the wood. The block with the bullet imbedded in it moves forward with a velocity of 7.7 m/s. What was the velocity (speed) of the bullet immediately before it hit the block (in m/s)

v = 1503 m/s

Explanation:

We will use the conservation of momentum to find the bullet's initial speed.

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.