Prepared By: Shakil Raiman
There are two kinds of physical quantities 1. Base Physical Quantities 2. Derived Physical Quantities
Base Physical QuantitiesSI UnitsSymbol for Units Lengthmeterm Masskilogramkg Timeseconds CurrentAmpereA TemperatureKelvinK Amount of substancemolemol Luminous Intensitycandelacd
Derived Physical Quantities SI UnitsSymbol for Units Speed, Velocitymeter/secondms -1 Accelerationmeter/second 2 ms -2 Force, WeightnewtonN Volumemeter 3 or cm 3 m 3 or cm 3 Densitykilogram/meter 3 kgm -3 or gcm -3 Momentumkilogram-meter/secondkgms -1 Momentnewton-meterNm
Derived Physical Quantities SI UnitsSymbol for Units Work Done, EnergyJouleJ PowerWattW Pressurenewton/meter 2, PascalNm -2, Pa ChargeCoulombC Potential DifferenceVoltageV
PrefixSymbolExponent TeraT10 12 GigaG10 9 MegaM10 6 kilok10 3 Decid10 -1 Centic10 -2 Millim10 -3 Micro Nanon10 -12
1 km = 1000 m 50 MW = W 1 mm = m 1 GHz = Hz 32 GB = B (approximately)
ScalarsVectors DefinitionA scalar is a quantity having magnitude (size) only A vector is a quantity having both magnitude and direction. OperationScalar can be added or subtracted simply Vectors can be added or subtracted graphically. Exampledistance, mass, length, time, volume, density, energy, speed, power, temperature etc. displacement, force, weight, moment etc.
Scalar: Simple addition or substruction. Example: 5kg + 3 kg = 8 kg 20 J + 60 J = 80 J Vectors: Vector can be added to form a RESULTANT. a. Simple algebraic addition when the vectors are parallel Example: 5 N (right) + 15 N (right) = 20 N (right) 15 N (right) + 5 N (left) = 10 N (right) b. Parallelogram addition when the vectors are not in the same straight line. Example: 6 N acting East and 8 N acting West. So 10 N acting. Check on board.
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