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Introduction to Physics. Physics. What is Physics? Physics is the mother of all sciences, it is to u nderstand the natural and what happens around us. Physics and Math. In Math we deal with Numbers only but in Physics we deal with Numbers and units. Ex In Math 4 + 4 = 8
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Physics What is Physics? Physics is the mother of all sciences, it is to understand the natural and what happens around us.
Physics and Math In Math we deal with Numbers only but in Physics we deal with Numbers and units. Ex In Math 4 + 4 = 8 But in Physics 4m + 4 cm = 4.04 m or 404 cm Another Ex 4 * 4 = 16 In Physics 4 m * 4 cm = 0.16 m2 or 1600 cm2
Basic Quantities(Units) Length, Mass, Time, Temperature and Electric charge. Length(L):- It is the distance (m, cm, mm, etc.) Mass(M):- It is the amount of matters (Kg, g, etc.) Time(t):- durations, clock, (Hr, min, sec, etc.) Temperature (T):- hot or cold (C, F, K) Electric charge:- No of flowing electrons (Col)
Derivable Quantities(Units) It is the quantity having rules (equations) depending on the basic quantities. Velocity, Acceleration, Force, Current, etc. The derivable quantities are so many. Ex. Force (F) F=m*a where m is mass (Kg), a is acceleration m/s2 Force unit is Newton(N) so N=Kg*m/s2
Scalars and vectors Scalarscan be determined by magnitude only. Vectorsneed magnitude and direction, (negative value mean opposite direction). Scalarslike Temperature, Pressure, Distance, etc. Vectorslike Force, Acceleration, Velocity, etc.
Standard systems of units There are many standard systems using differ units the common types in SI (International system) and British or American standard. Ex Length unit in SI is m or cm but in American or British system is ft or in. Units create by scientists in labs using measurement devices and making calibration to identify the unit clear.
Accuracy and Error No measurement can be done with 100%, there is always error even it is in Nano unit. The error comes from devices or humans or environment conditions. But as we know a small error can be neglected so we minimize the error as possible. Ex 1 m and the error is 2*10 -7 the error is too low so we can neglect it.
Numerical sense and approximate We must feel the answer we write is it acceptable or not. Ex distance between Cairo and Alex = 4 cm It is not acceptable because always these types of distance measured in Km or miles. We must approximate the final answer to 2 or 3 digit. Ex L = 0.6432561 m it is 0.64 m or 0.643 m that is enough cause we can neglect the smaller value