Witch statement best describes why a machine is useful

"A machine can decrease either the input force or the input distance needed to do a given amount of work" statement best describes why a machine is useful.

Explanation:

A machine is any kind of instrument, apparatus or mechanism which has the ability to reduce the amount of work done by humans or by mechanical force. It uses power in terms of electrical energy to generate the force acting on any object for a particular job.

So the work done is dependent on the force acting on any object and the displacement done on the object. As the power in form of electrical energy generates the force acting on the object, the machine can reduce the input force or input distance needed to do a given amount of work by varying the angle of acting of force.

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.