Can physics measure the work a porter does? What do you need to know to measure a porters work? What produces work, and how is power different from work?

No

Explanation:

According to physics, the work done by porter is zero but in reality porter gets tired as muscular energy is being used up.

In physics, work is the dot product of force and displacement. when the porter moves with the luggage, the weight act downwards while the porter moves forward. The angle between force and displacement is 90°. Thus, work done by the porter is zero.

The muscles are doing work in this case which is not calculated in physics.

Power is the rate of energy consumed during the work.

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.