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Matter: Matter is any substance or material that occupies space and has mass. Matter can exist as a Solid, Liquid or Gas. These are called the three states of matter. For example: Wood, Chair, Soil, Animals etc. Matters are of 2 types I) Living Matter :Man, Animal etc II) Non - Living Matter: Chair, Soil, Building etc Energy: Energy is the capacity of a body to do work. Both people & machines use energy to do work. For example: Light, Heat, Sound etc.

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Mass: Mass is the amount of matter in something. it depends on the number of atoms it contains and the size of those atoms. it is a basic property of an object and cannot be changed by the location, shape and speed of the object. The SI unit for mass is the Kilogram (kg). Gravitational field strength (G. F. S): The gravitational field strength, g, is defined as gravitational force acting per unit mass on an object. on earth, the gravitational field strength is 10 N/kg. i.e a 1 kg object has a force of 10 N pulling on it due to earth. G.F.S on the moon is 1.6 N/kg.

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Weight: The weight of a body is the gravitational force with which the earth attracts the body. The weight of a body is the force that causes it be accelerated down word with the acceleration of gravity (g) Weight= Mass Gravitational field strength W = m g where, m=Mass of the object g=Gravitational field strength Weight is measured in Newton (the unit for force)

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A 100 kg man slides down a rope at constant speed What minimum breaking strength must the rope have? Since the man slides down at constant speed, the rope must support his weight. So here W=mg =100 10 = 1000N

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Total mass of an object is 120 kg. What will be: I) Weight on Earth? II) Weight on the Moon? III)Mass on the Moon? Here, Mass, m=120 kg on earth g earth =10N/kg on moon g moon =1.6 N/kg I) weight on earth, W earth = m g earth =120 10 =1200N Ans II) weight on moon, W moon =m g moon =120 1.6 =192N Ans III) Mass on moon = 120 kg Ans

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Difference between Mass and Weight MassWeight I) is the amount of matter in the body I) is the pull of gravity on the body II) has only magnitude but no direction II)Weight has both magnitude and direction III)is measured in kilogramsIII)is measured in Newton IV)Mass is constantIV)changes from place to place A rock on the moon has a mass of 0.5 kg. It is brought to the earth where the gravitational field is strong. On the earth the rock will have: i) less mass & less weight ii) less mass & same weight iii) the same mass & same weight iv) the same mass & more weight

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If a person has a mass of 60 kg on the earth, how much will be weight on the moon. Volume: Volume is the amount of space something takes up. Volume= length height width The SI unit of volume is the cubic meter(m 3 ). 1 m Here Volume = 1 m 1m 1m = 1 m 3 The volume of a liquid is measured in liter. Mass, m=60 kg g=1.6 N/kg weight on earth, W= m g =60 1.6 =96N Ans 1m

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Density: The density of a substance is defined as the amount of matter contained in a unit volume of the substance. Density of some common substance The SI unit of density is kilogram per cubic meter (kg/m 3 ) p=Density m=Mass v=Volume SubstanceDensity Air1.29 Pure water1000 Sea water1025 Mercury13600 SubstanceDensity Ice920 Aluminum2700 lead11000 Gold19000

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If we take same volume of water and mercury then which one is more heavier and why? Mercury is much heavier than water because the density of mercury is more then the density of water. A box 0.4 m long, 0.3 m wide and 0.1 m height, has a density of 2500 kg/m 3. Calculate its mass. Here, Length(l)= 0.4 m Wide (w) = 0.3 m Height(h)= 0.1 m Density(P)= 2500 kg/m 3 V=l w h =0.4 0.3 0.1 =0.012m 3 We know m=p v =2500 0.012 =30 kg Ans

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A 500 cm 3 glass flask is filled with oxygen and measure. The mass is found to be 50.72 g. By means of a vacuum pump, the oxygen is then removed and the glass flask is again measured. The new mass is found to be 50.00 g. Calculate the density of oxygen. Here, Mass(m1)= 50.72 g Mass(m2) = 50.00 g Volume(v)= 500 cm 3 mass of oxygen = (m1 – m2) = (50.72 – 50.00) = 0.72 g We know =0.72 / 500 = 0.00144 g/cm 3 Ans A block of aluminum has a volume of 2m 3 and the density of 2700 kg/m 3. What is its mass? We know m =p v = 2700 kg/m 3 2 m 3 =5400 kg Ans

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