Aweather balloon, rising vertically at 25.0 m/s, releases an instrument package when it is 100. meters above the ground. how many seconds does it take from when the package was released for the package to hit the ground?

7.74 seconds

Explanation:

u = 25 m/s

h = - 100 m

Let it takes time t to hit the ground.

Use second equation of motion

Take positive sign as time can never be negative.

t = 7.74 s

Thus, the package takes 7.74 seconds to reach the ground.

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.

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