CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
Differences between mass and weight
Mass
Weight
1. Mass is amount of matter inside an
object which resists changes in state of
motion ( inertia)
1. Weight is gravitational pull acting an
object (force)
2. Mass is a scalar a quantity
3. Weight depends on gravitational field
strength
3. Mass remains constant
4. Mass is measured by electronic
balance
2. Weight is a vector quantity
4. Weight is measured using a newton
meter
5. SI unit of mass is kg
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5. SI unit of weight is Newtons, N
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CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
(m/19/P22)
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2
CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
(m/19/P22)
Difference between two diagrams
is half the liquid
= 1.30 - 0.90
= 0.40 kg
If we subtract further 0.40 kg
from 0.90 kg we will get mass of
empty bottle
= 0.90 kg - 0.40 kg = 0.50 kg
Correct option is C
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3
CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
2.2 gravitational field strength
Gravity: (property linked with mass)
Gravitational field strength:
It is defined as gravitational force
acting per unit mass of an object
g = W
m
W = gravitational force, N
m = mass, kg
Gravitational field: Region around a
large mass where a small mass
experience a gravitational pull
g = gravitational field strength, Nkg-1
Gravitational field strength depends
on mass of planet
Represented by gravitational field
lines
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CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
2.2 gravitational field strength
e.g
An object has a mass of 55 kg and a
weight of 539 N on earth.
i) find gravitational field strength of
earth
ii) find weight of the same object on
moon where gravitational field strength
is 1.6 Nkg-1
ii)
g = W
m
W = m g
= 55 x 1.6
= 88 N
i) g = W
m
g = 539 = 9.8 Nkg-1
55
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CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
(s/20/P11)
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CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
(s/20/P11)
g = W
m
A) g = 125/5 = 25
B) g = 150/15 = 10
C) g = 220/20 = 11
D) g = 225/25 = 9
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Correct option
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CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
(w/20/P12)
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8
CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
(w/20/P12)
On planet, object mass gives reading of 1 kg but the instrument is designed for
earth.
On Earth, since the gravity is five times stronger , the spring balance will give
reading five times more i.e 5 kg
If each rock is 0.1 kg and total is 5 kg. Then number of rocks will be
5 ÷ 0.1 = 50 rocks Correct option is D
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9
CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
(m/20/P22)
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CAIE | Notes | Physics 5054 | Chapter 3 Mass and weight | 2.1 mass and weight
(m/20/P22)
The mass remains unchanged. So A and B are rejected
Since weight is directly proportional to gravitational field
strength, the weight will
Weight will decrease. Correct option will be A
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11