1. 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.

2. Mass: Mass is the amount of matter in something
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.

3. Weight= Mass  Gravitational field strength W = m  g
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)

4. 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

5. 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 gearth = 10N/kg
on moon gmoon = 1.6 N/kg
I) weight on earth,
Wearth = m  gearth
=120  10
=1200N Ans
II) weight on moon,
Wmoon = m  gmoon
= 120  1.6
= 192N Ans
III) Mass on moon = 120 kg Ans

6. I) is the amount of matter in the body
Difference between Mass and Weight
Mass
Weight
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 kilograms
III)is measured in Newton
IV)Mass is constant
IV)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

7. If a person has a mass of 60 kg on the earth, how much will be weight on the moon.
Mass, m = 60 kg g=1.6 N/kg
weight on earth,
W = m  g =60  =96N Ans
Volume: Volume is the amount of space something takes up.
Volume= length  height  width
The SI unit of volume is the cubic meter(m3). 1m
The volume of a liquid is measured in liter. 1m
1 m
Here Volume = 1 m  1m  1m = 1 m3

8. Substance Density Substance Density
Density: The density of a substance is defined as the amount of matter contained in a unit volume of the substance.
p = Density
m = Mass
v = Volume
The SI unit of density is kilogram per cubic meter (kg/m3)
Density of some common substance
Substance
Density
Air
1.29
Pure water
1000
Sea water
1025
Mercury
13600
Substance
Density
Ice
920
Aluminum
2700
lead
11000
Gold
19000

9. 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/m3. Calculate its mass.
Here,
Length(l) = 0.4 m
Wide (w) = 0.3 m
Height(h) = 0.1 m
Density(P)= 2500 kg/m3
V=l  w  h
= 0.4  0.3  0.1
= 0.012m3
We know
m = p  v
= 2500 
= 30 kg Ans

10. A 500 cm3 glass flask is filled with oxygen and measure
A 500 cm3 glass flask is filled with oxygen and measure. The mass is found to be 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 g. Calculate the density of oxygen.
Here,
Mass(m1) = g
Mass(m2) = g
Volume(v)= 500 cm3
mass of oxygen = (m1 – m2)
= (50.72 – 50.00)
= 0.72 g
We know
= 0.72 / 500 = g/cm3 Ans
A block of aluminum has a volume of 2m3 and the density of 2700 kg/m3. What is its mass?
We know
m =p  v = 2700 kg/m3  2 m3 =5400 kgAns