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The speed with which the man flies forward is 5.5 m/s

Explanation:

The mass of the man = 100 kg

The mass of the scooter = 10 kg

The speed with which the man was traveling on the scooter = 5 m/s

The speed of the scooter after it hits the rock = 0 m/s

Let v represent the speed with which the man flies forward

The formula for momentum, P, is P = Mass × Velocity

The conservation of linear momentum principle is, the total initial momentum = The total final momentum, therefore, we have;

The total initial momentum = (100 kg + 10 kg) × 5 m/s = 550 kg·m/s

The total final momentum = 100 kg × v + 10 kg × 0 m/s = 100 kg × v

When the momentum is conserved, we have;

550 kg·m/s = 100 kg × v

∴ v = 550 kg·m/s/(100 kg) = 5.5 m/s.

The speed with which the man flies forward = v = 5.5 m/s

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.