While newton's second law often deals with formulas and numerical calculations, there exist one very important nonnumerical convention that must be appreciated and adhered to. on september 23, 1999, mars climate orbiter--a $125 m space mission--was lost when a small rocket was fired to adjust entry to the mars atmosphere. unfortunately, one operator assumed the thrust value was given in english units when actually nasa specifications gave it in metric units. this is an example of consequences if the mks convention is not precisely honored. what does the mks convention designates the following? a) measure distance in miles, mass in kilograms and time in seconds b) measure distance in meters, mass in kilograms and time in seconds c) measure mass in newtons, distance in kilometers and time in seconds d) measure time in minutes, distance in kilometers, mass in kilograms

Option B is the correct answer.

MKS system gives the following units:

Distance meters

Mass Kilograms

Time seconds

meter is basic unit for length measurement. smaller units are centimeter, millimeter, micrometer, bigger units are kilometer and so on.

kilogram is the basic unit for mass. smaller unit is gram.

second is the basic unit for time. Greater units are minutes, hours, smallest unit are micro second and so on.

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.

this is poiselle's equation from fluid mechanic in physics. mech eng