A Navy Seal of mass 80 kg parachuted directly down into an enemy harbor. At one point while she was falling, the resistive force that air exerted on her was 520 N upward. What can you determine about her motion at this point in time

The Navy Seal is accelerating downwards at the rate of 3.3 m/s²

Explanation:

Given;

mass of the Navy Seal, m = 80 kg

the upward resistive force on her, F = 520 N

Her net downward force is given by;

Her downward acceleration at this time is given by;

F = ma

a = F / m

a = 264 / 80

a = 3.3 m/s²

Therefore, the Navy Seal is accelerating downwards at the rate of 3.3 m/s²

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.

-4 on