Physics Unit 0

​measurements , volume and density

physical quantity is a quantity described to phenomenon , substance and objects and can be quantified

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BASIC PHYSICAL QUANTITY is a quantity that cannot be divided from one another , they are used as the basics for measuring

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DERIVED PHYSICAL QUANTITY are quantities that can be divided from one another through multiplication , division or both.

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SI UNITS are the standard unit used for a quantity internationally

LENGTH METRE M

MASS KILOGRAM KG

TIME SECONDS

SCALAR - has magnitude , no direction

example : speed

vector - has both

example : velocity

​ length time

​-length is distance between 2 points

-SI unit : meter

​-time is duration of a physical process

-SI unit : seconds

​volume

​space occupied by an object

v for cube = l x l x l

v for cuboid = l x b x h

v for cylinder = pi r^2 h

​method 1: fill a cylinder with water and mark

the point v1 . then drop in irregular object , when water level rises , mark new spot as v2 .

v2 - v1

​method 2: fill displacement can with water till it overflows . when it stops , place measuring cylinder below it . lower irregular shaped object , the water collected in measuring cylinder is the volume

​DENSITY

​density of an object is its mass per unit volume

density = m / v

m = mass

v = volume

si unit = kg/m^3 or g/cm^3

​distance AND dislacement

distance is the ​total path length between 2 points , meter is the SI unit.

displacement is defined as the straight distance between initial and final position

​speed

​s=d/t

SI unit=m/s

velocity

​rate of change of displacement over time

v=d/t

SI unit=m/s

vector

​difference between speed and velocity

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1. speed is scalar

2. velocity is vector

​acceleration

​acceleration is the rate of change of velocity

something is accelerating if its velocity is changing

change in speed or direction can lead to this

A=v-u/t

acceleration is equal to final velocity-intitial velocity over time