1. An insect inside a bus flies from the back toward the front at 2 m/s. The bus is moving in a straight line at 20 m/s. What is the total speed of the insect as seen by a person standing on the
side of the road?

Total speed of the insect as seen by a person standing on the side of the road is 22 m/s

Explanation:

There i a composition of velocities, since the air inside the bus is moving at the same speed as the bus, and the insect flying relative to it.

So for an observer on the side of the road, the insect is flying at a speed of :

20 m/s + 2 m/s = 22 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.

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