Ferns spread spores instead of seeds, and some ferns eject the spores at surprisingly high speeds. one species accelerates 1.4 μg spores to a 4.5 m/s ejection speed in a time of 1.0 ms. what impulse is provided to the spores? what is the average force on a spore?

Impulse is

The average force is

Explanation:

When a mass undergoes a change in velocity , its impulse is

and if a force is acting for time , then the impulse is given by

Now the mass of the spores in kg is

we calculate the impulse from the first formula:

Now that we have impulse, we calculate the average force on the spore from the second formula:

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.