Physics Questions

PWC refers to Personal Water Crafts.

To control steering on a PWC, the most needed requirement is to have power in which will allows the one using it to control the engine for it to stop or for it to move. Without power, the person using it could be out of balance or fail to start the engine. This is the basic requirement because even though it is shut off or the engine is off, the PWC is still on and it could still move without proper knowledge of the engine.

It is useful to have a property of a material that is independent of the size of the sample and can be use to compare its elastic properties with another - this is called the Modulus of Elasticity for the material.

The modulus of elasticity is defined as:

Modulus of elasticity = Stress / Strain

There are three types of moduli. They are :

(a) the Young Modulus - tensile and compression longitudinal stress

(b) the shear modulus - a shearing stress

(c) the bulk modulus - volume changes of the specimen.

Fog is tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Hence, fog is an example of a colloidal system liquid dispersed in gas.

At the time of jumping out he has the same velocity as the moving train

C2H6O is a Non-electrolyte.

An electrolyte is a compound that conducts an electric current when it is in an aqueous solution or melted. In order to conduct a current, a substance must contain mobile ions that can move from one electrode to the other. All ionic compounds are electrolytes. When ionic compounds dissolve, they break apart into ions which are then able to conduct a current ( conductivity ). Even insoluble ionic compounds such as CaCO 3 are electrolytes because they can conduct a current in the molten (melted) state.

A nonelectrolyte is a compound that does not conduct an electric current in either aqueous solution or in the molten state. Many molecular compounds, such as sugar or ethanol, are nonelectrolytes. When these compounds dissolve in water, they do not produce ions.

Electrolytes are of 3 types ---- Strong Electrolytes, Weak Electrolytes and Non Electrolytes.

Strong Electrolytes ---- Compounds which completely dissolves. ( NaCl, Na2Co3, HCl )

Weak Electrolytes ----- Compounds which do not completely dissolves.

Non Electrolytes ------ Compounds which do not dissolves at all.

Flows out of Newton's first law of motion.

The atmospheric pressure at the surface of the Earth is due to gravitational pull of the earth and is about 14.7 psi.

That means that the weight of a column of air which has a cross section of 1 square inch and which stretches from the surface of the Earth to space is 14.7 pounds. 

Aluminium being a good conductor of heat conducts away the heat from the substance quite easily and causes quick freezing.