Work, Force and Energy Notes

Grade IV

Question 1: What is force?

Answer: Force is a push or pull applied to an object.

Question 2: What can force do to a moving object?

Answer: Force can speed it up, slow it down, or change
its
direction.

Question  3:
Can force
change the shape of an object?

Answer: Yes, force can change an object’s shape.

Question 4: What are some types of forces?

Answer: Muscular force, gravitational force, and
frictional
force are different types of forces.

Question 5: What is elastic force?

Answer: It is the force that arises when something is
stretched or compressed, like a rubber band or spring.

Question 6: How is elastic force created?

Answer: By the particles of rubber or spring resisting
being
stretched.

Question 7: What is muscular force?

Answer: It is the force that arises due to the working
of
muscles, used to lift objects or do exercises.

Question 8: What is gravitational force?

Answer: It is the force that pulls everything down
towards
the Earth, also known as gravity.

Question 9: What would happen without gravitational
force?

Answer: We would be floating in the air.

Question 10: What is frictional force?

Answer: It is the force that opposes motion when two
surfaces rub against each other, slowing down and eventually stopping a
moving
object.

Question 11: What is work in terms of physics?

Answer: Work is done when a force applied to an object
moves
it from its position.

Question 12: How do simple machines help us?

Answer: Simple machines make our work easier by
allowing us
to apply force more effectively.

Question 13: What is energy?

Answer: Energy is the ability to do work.

Question 14: Can energy be created or destroyed?

Answer: No, energy can only be converted from one form
to
another.

Question 15: What is gravity?

Answer: Gravity is the force that pulls everything down
towards the Earth.

Question 16: What is friction?

Answer: Friction is the force that opposes motion.

Question 17: What is a simple machine?

Answer: A simple machine is a device that makes our
work
easier.

Question 18: What is energy in science?

Answer: Energy is what we need to do work.

Question 19: What are fossil fuels?

Answer: Fossil fuels are substances from deep inside
the
Earth that release energy when burned.

Question 20: How does a machine make our work easier?

Answer: A machine makes our work easier by letting a
smaller
force overcome a bigger force and by making work more convenient by
changing
the direction of the force.

Question 21: What are some examples of simple machines?

Answer: Examples of simple machines include levers,
pulleys,
wheels and axles, inclined planes, wedges, and screws.

Question 22: What is a pulley?

Answer: A pulley is a simple machine with a grooved
wheel
that holds a rope or cable.

Question 23: What does a pulley do?

Answer: It is used to lift heavy objects more easily
and
change the direction of the force.

Question 24: Can you give examples of where pulleys are
used?

Answer: Pulleys are used in a village well to draw
water and
in a crane to lift loads.

Question 25: What is a wheel and axle?

Answer: It is a simple machine that consists of one or
two
wheels connected to a rod called an axle.

Question 26: How does a wheel and axle work?

Answer: When the wheel turns, the axle turns too. This
setup
allows a small force applied at the wheel to move a heavy object at the
axle.

Question 27: Can you provide some examples of a wheel
and
axle?

Answer: Yes, a steering wheel, an egg beater, and a
door
handle are examples of a wheel and axle.

Question 28: What is an inclined plane?

Answer: An inclined plane is a sloping surface that
makes it
easier to raise or lower a load.

Question 29: Why is less effort needed with an inclined
plane?

Answer: Less effort is needed to move a heavy object up
an
inclined plane than to lift it straight up.

Question 30: Can you give an example of an inclined
plane?

Answer: A smooth, long, wooden board placed slanting on
something is used as an inclined plane. Other examples include ramps used
for
loading and unloading trucks, and the slider in a school playground.

Question 31: What are ideal inclined planes used for?

Answer: Ideal inclined planes, like ramps, are used to
make
it easier to move to a higher location, like for people in wheelchairs
instead
of using stairs.

Question 32: What happens when the slope of an inclined
plane is gentle?

Answer: If the slope is gentle, a person has to push or
pull
the object over a longer distance, but it requires little effort.

Question 33: What happens when the slope of an inclined
plane is steep?

Answer: If the slope is steep, a person has to push or
pull
the object over a short distance, but it requires more effort.

Question 34: Can you list some other fields where
inclined
planes are used?

Answer: Besides ramps for wheelchairs and slides,
inclined
planes are used in construction sites for moving materials and at loading
docks
for moving goods.

Question 35: What is a wedge?

Answer: A wedge is a simple machine that consists of
one or
two slanting planes that come together to form a sharp edge.

Question 36: What is a wedge used for?

Answer: A wedge is used in cutting, splitting, and
piercing.

Question 37: Can you give some examples of wedges?

Answer: Yes, examples of wedges include an axe and
various
piercing tools.

Question 38: What is a screw?

Answer: A screw is like an inclined plane wrapped
around a
rod with a pointed end.

Question 39: What does a screw do?

Answer: It is used to hold two things tightly together.

Question 40: How does a screw work?

Answer: As it turns, it moves downwards through a
greater
distance than the force applied, which allows a smaller force to produce a
large downward force.

Question 41: What is energy?

Answer: Energy is the ability to do work.

Question 42: Why do we need energy?

Answer: We need energy to do everything in our lives,
such
as read, write, eat, jump, play, and sing.

Question 43: Can we see energy?

Answer: No, we cannot see energy, but we can see its
effects.

Question 44: Do living beings need energy?

Answer: Yes, all living beings need energy to do work.

Question 45: Can energy change forms?

Answer: Yes, one kind of energy can be converted to
another
kind of energy.

Question 46: What is the main source of energy on
Earth?

Answer: The Sun is the main source of energy on Earth.

Question 47: What is the energy from the sun called?

Answer: The energy from the sun is called solar energy.

Question 48: Which organisms can trap the sun’s energy?

Answer: Only green plants can trap the sun’s energy by
the
process of photosynthesis.

Question 49: How is food energy transferred among
living
beings?

Answer: Food energy gets transferred from plants to
animals
through the food chain.

Question 50: Do animals depend on plants for energy?

Answer: Yes, all animals directly or indirectly depend
on plants
for food.

Question 51: What is one way humans use to trap solar
energy?

Answer: Solar panels are used to trap solar energy,
which
can be used to produce electricity.

Question 52: What are some types of fuels?

Answer: Coal, petroleum, and kerosene are types of
fuels.

Question 53: What kind of energy do fuels like coal,
petroleum, and kerosene have?

Answer: They have chemical energy.

Question 54: What happens when fuels are burned?

Answer: The chemical energy gets transformed into heat
and
light energy.

Question 55: What is the energy from the wind called?

Answer: The energy from the wind is called wind energy.

Question 56: What is wind energy used for?

Answer: Wind energy is used to rotate the fans of
windmills
to produce electricity.

Question 57: What is the energy in flowing water known
as?

Answer: Water energy.

Question 58: What is the energy of moving water used
for in
power generation?

Answer: To rotate the turbines of generators.

Question 59: What do we call the electricity generated
from
the energy of moving water?

Answer: Hydroelectricity.

Question 60: What is the name given to a power station
that
generates electricity from water energy?

Answer: Hydro power station.

Question 61: What is the energy produced by splitting
an
atom known as?

Answer: Atomic energy.

Question 62: Where is atomic energy used to produce
electricity?

Answer: In nuclear power plants.

Question 63: Is atomic energy a clean source of energy
in
terms of air pollution?

Answer: Yes, it does not cause air pollution.

Question 64: Why does the use of atomic energy need to
be
monitored closely?

Answer: Because it can be used for destructive
purposes,
like in a nuclear bomb, and causes great destruction to life and property.

Question 65: Can energy be created or destroyed?

Answer: No, energy can neither be created nor
destroyed.

Question 66: What can be done with energy?

Answer: It can only be converted from one form to
another.

Question 67: Give an example of energy conversion.

Answer: Electrical energy can be changed into light and
sound energy.

Question 68: Why do humans convert one form of energy
to
another?

Answer: To do work.

Question 69: What are coal and petroleum classified as?

Answer: Fossil fuels.

Question 70: Where are fossil fuels found?

Answer: Deep inside the Earth.

Question 71: What do fossil fuels produce when burned
that
pollutes the air?

Answer: Carbon dioxide and other gases.

Question 72: Are fossil fuels renewable or
non-renewable?

Answer: Non-renewable.

Question 73: Why should we reduce the usage of fossil
fuels?

Answer: Because they exist in limited quantity and are
not
easily replenished.

Question 74: Does energy have a cost in nature?

Answer: No, it exists freely in nature.

Question 75: What is the term for energy forms that
never
run out?

Answer: Renewable.

Question 76: Which forms of energy are considered
non-renewable?

Answer: Coal, petroleum, natural gas, and kerosene.

Question 77: What are examples of renewable energy?

Answer: Solar energy, wind energy, hydropower, and
forest.

Question 78: How has the usage of energy changed
compared to
a century ago?

Answer: People use more electronics, automobiles, and
home
appliances now.

Question 79: What should one do apart from saving
energy?

Answer: Practice and make others aware of ways to save
energy.

Question 80: What are different effects of force?

Answer: The different effects of force include:

• ·        
  Moving a resting object
• ·        
  Speeding up a moving object
• ·        
  Changing the direction of a moving object
• ·        
  Slowing down a moving object
• ·        
  Stopping a moving object
• ·        
  Changing the shape of an object