Answer:
b. The normal force between the molecules of the paper is overcome by the contact force of the hands.
Explanation:
The paper molecules are held together by a weak bond. When the student holds the paper on both sides with the center of the paper in between, the student applies two equal forces in the opposite direction of the paper making the paper molecules weaken and separate.
Pure substances can be elements made up exclusively of one kind of atom, or they can be compounds made up of molecules that include two or more elements. Mixtures can be homogeneous or heterogeneous depending on how finely mixed the components are.
Answer:

Explanation:
Mass of the helium gas filled inside the volume of balloon is given as




now total mass of balloon + helium inside balloon is given as


now we know that total weight of balloon + cargo = buoyancy force on the balloon
so we will have




Water has a high specific heat capacity. Oil has a smaller heat capacity.