Mass What is mass Mass is the measure

Mass What is mass? Mass is the measure of the amount of substance in a body Units SI units: kg Other units: g, tonne Conversion 1 kg = 1000 g 1 ton = 1000 kg Can calculate what is 1 ton in grams? If mass in kilograms, what about weight? Shouldn’t weight be in kilograms instead?

Mass Measuring Mass The instruments used to measure mass are 1. Electronic balance 2. Beam balance

Weight What is weight The weight of a body is the pull of gravity on that body Units SI units: N (newton) Newton’s 2 nd law Since weight is a force, it must be a vector… So which direction is our weight pointing? Force = mass x acceleration Weight = mass x acceleration due to gravity W = m x g

Weight Acceleration due to gravity Planets Sun Mercury Venus Earth Moon Mars Jupiter Saturn Uranus Neptune Pluto Acceleration Due to Gravity Comparison Acceleration Due Mass [kg] Radius [m] g / g-Earth to Gravity, "g" [m/s 2 ] 1. 99 x 1030 3. 18 x 1023 4. 88 x 1024 5. 98 x 1024 7. 36 x 1022 6. 42 x 1023 1. 90 x 1027 5. 68 x 1026 8. 68 x 1025 1. 03 x 1026 1. 40 x 1022 6. 96 x 108 2. 43 x 106 6. 06 x 106 6. 38 x 106 1. 74 x 106 3. 37 x 106 6. 99 x 107 5. 85 x 107 2. 33 x 107 2. 21 x 107 1. 50 x 106 274. 13 3. 59 8. 87 9. 81 1. 62 3. 77 25. 95 11. 08 10. 67 14. 07 0. 42 27. 95 0. 37 0. 90 1. 00 0. 17 0. 38 2. 65 1. 13 1. 09 1. 43 0. 04

Weight Measuring Mass The instruments used to measure mass are 1. Electronic balance 2. Beam balance

Mass Vs Weight Get into groups of 4 and discuss: The differences between mass and weight 10 mins

Class Activity • Give the raw egg hard spin on its side • Stop the spin by placing a fingertip on the egg, the quickly lift the finger • What do you observe as you lift the finger?

Inertia What is inertia? It is the reluctance of a body to start moving if it is stationary in the first instance OR It is the reluctance of a body to stop moving if it is moving in the first instance

Inertia 100 kg Vs 20 kg Who is easier to push? Who is easier to stop? 100 kg 20 kg

Density Container A Container B Can you tell the difference between the 2 containers?

Density What is density? Density is defined as mass per unit volume Density = mass/volume Units M SI units: kg/m 3 Other units: g/cm 3 D V My Dear Valentine

Density Object Mass/g Vol/cm 3 Aluminium sheet 50 18. 52 Gold bracelet 150 Water Density g/cm 3 Sink or Float? 2. 70 Sink 7. 89 19. 0 Sink 500 1 --- Ice 10 10. 87 0. 92 Float Block of pinewood 800 1600 0. 5 Float

Density Get into groups of 4 and discuss: How you would help the King identify whether the crown was made of pure gold or not? Write your answers on the mahjong paper provided Present your solution to the class next lesson

Concept Map kg/m 3 Densit y Mass per unit volume defined as related to mass by D = M/V related to density by defined as Mass, m kg related to weight by is a measure of W=mxg related to mass by N Weight where defined as Amount of substance in a body inertia g is the gravitational force per unit mass acting on an object Gravitational force acting on an object