Answer: Option (a) is the correct answer.
Explanation:
Resources which are created by human beings are known as man-made resources.
For example, glass, rayon, nylon etc are all man-made resources.
Whereas resources which are naturally created are known as natural resources.
For example, wind, air, water etc are all natural resources.
Thus, we can conclude that out of the given options time is not a natural resource.
Answer:
D. 4Al + 3O2 → 2Al2O3
Explanation:
Chemical reactions involves the chemical combination of two or more substances called REACTANTS to yield other substances called PRODUCTS. However, in accordance with the LAW OF CONSERVATION OF MASS, the amount of reactants must be equal to that of the products.
To accomplish this, the reaction must be BALANCED. A balanced equation is an equation in which the number of atoms of each element in the reactant side equals the number of atoms in the product side. In this reaction involving Aluminum and Oxygen to give Aluminum oxide as follows:
Al + 02 → Al2O3
A coefficient is used to balance the number of atoms on both sides of the equation as follows:
4Al + 3O2 → 2Al2O3
Answer:
Rolling friction is much smaller than sliding friction because Rolling friction is considerably less than sliding friction as there is no work done against the body that is rolling by the force of friction. For a body to start rolling a small amount of friction is required at the point where it rests on the other surface, else it would slide instead of roll.
Rolling Friction example: Anything with weels (cars,skateboards) or a ball rooling.
Sliding Friction example: Bicycle brakes,skinning your knee walking,writing.
Answer:NO
Explanation:
No the mold should not be of the same size as that of sculpture because the material from which molds is made may shrink or expand depending upon its properties .
For example grey cast iron shrinks on cooling.
We need to make mold bigger in general so that if there is a need of finishing it can be done easily without altering the size of sculpture.
Answer:
temperature measures heat - the unit is Celsius - and it is measured with a thermometer.
length is measuring how long, tall, or wide something is - the base unit it metres - and it is measured with a ruler or a metre stick
volume is measuring the quantity of a three dimensional space - the unit is cubic centimetre - you find volume by taking the measurements with a ruler
mass is measuring how much space something takes up/ weight - unit is the gram - you use a scale
