A theory isn't certain, it exists as long as it is based on logic, but until an evidence is shown that fully confirms it, the theory remains just a possibility. A change in a theory means it is proven wrong and ceases to exist, which leads to the creation of a new theory.
25/35 of the project is completed
12 people can do 1/35 a day
you need to do 10/35 in 5 days
12 people can do 5/35 in 5 days
so you need twice as more people
First: When energy passes into or out from a system, the system's internal energy changes in accord with the law of conservation of energy.
Second: In a natural thermodynamic process, the sum of the entropies of the interacting thermodynamic systems increases.
Third: The entropy of a system...
A-(B⋂C)=(A-B)⋃(A-C) If A-B={xlx∈A and x∉B} A-C={xlx∈A and x∉C} then (A-B)⋃(A-C)={xlx∈A, x∉(B and C) Let X=A and Y=(B⋂C) X-Y={xlx∈X and x∉Y} x∉Y x∉(B⋂C) x∉(B and C) physicsforums