Balbharti Maharashtra State Board Class 6 Science Solutions Chapter 12 Simple Machines Notes, Textbook Exercise Important Questions and Answers.

Class 6 Science Chapter 12 Simple Machines Textbook Questions and Answers

1. Classify the following as a lever, a pulley and an inclined plane:
(A wedge, a needle, a staircase, a slide, the wheel of a flagpole, nutcrackers, scissors, an opener, an axe, a crane, a knife)

Question a.
Classify the following as a lever, a pulley and an inclined plane:
(A wedge, a needle, a staircase, a slide, the wheel of a flagpole, nutcrackers, scissors, an opener, an axe, a crane, a knife)
Answer:

Inclined plane	Pulley	Lever
Wedge	Wheel of flagpole	Nutcracker
Needle	Crane	Scissors
Staircase		Opener
Slide
Axe
Knife.

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2. Fill in the blanks using the proper word and complete the statements.

Question a.
The ………….. in the centre, the ………….. on one side and the on the ………….. other side make a lever of the first order.
Answer:
Fulcrum, load and effort

Question b.
The ………….. in the centre, the ………….. on one side and the ………….. on the other side make a lever of the second order.
Answer:
Load, fulcrum, effort

Question c.
The ………….. in the centre, the ………….. on one side and the ………….. on the other side make a lever of the third order.
Answer:
Effort, fulcrum, load

3. Which machines will you use to do the following work? Write their types.

Question a.
To remove the lid of a tin. Opener Lever of the second order
Answer:

Question b.
To lift bricks to the top of a tall building Crane Complex machine
Answer:

Question c.
To cut vegetable Knife Wedge – Simple machine
Answer:

Question d.
To draw water from a well Pulley Simple machine
Answer:

Question e.
To hold a papad for roasting it. A pair of tongs Lever of the third order
Answer:

4. Write the answers to the following questions in your own words. 

Question a.
What is meant by a simple machine?
Answer:

Question b.
Mention the advantages of using a machine.
Answer:

Question c.
What is meant by a complex machine?
Answer:

Question d.
What is a lever? How is the order of the lever determined?
Answer:

5. Why is this so?

Question a.
Traveller’s bags have wheels.
Answer:

Question b.
Machines have to be maintained.
Answer:

Question c.
A bicycle is said to be a complex machine.
Answer:

6. Name the levers mentioned in the following passage. Identify the fulcrum, load and effort of each and say which type of lever it is.

Ravi and Savita sit on a sea-saw in a garden. In the mean time, a gardener is trimming trees in the garden. He puts the leaves and other garbage in the wheelbarrow. Later, Ravi gets thirsty and he buys lemon sherbet. The sherbet seller cuts the lemon and squeezes it using a lemon squeezer. He puts small pieces of ice in the glass with the help of the tongs.

Question a.
Name the levers mentioned in the following passage. Identify the fulcrum, load and effort of each and say which type of lever it is.

Ravi and Savita sit on a sea-saw in a garden. In the mean time, a gardener is trimming trees in the garden. He puts the leaves and other garbage in the wheelbarrow. Later, Ravi gets thirsty and he buys lemon sherbet. The sherbet seller cuts the lemon and squeezes it using a lemon squeezer. He puts small pieces of ice in the glass with the help of the tongs.
Answer:
Levers:

Activity:

Question 1.
Make a list of the various machines used in your home and neighborhood and write their types.

Question 2.
Go to a bicycle repair shop, observe how a bicycle is repaired, and note down the information.

Class 6 Science Chapter 12 Simple Machines Important Questions and Answers

Fill in the blanks.

Question 1.
Simple machines can be handled ………….. .
Answer:
easily

Question 2.
The structure of complex machine is ………….. .
Answer:
complicated

Question 3.
The more gradual the the ………….. lesser is the we bear. But, such an inclined plane is ………….. .
Answer:
slope, weight, longer

Question 4.
The steeper the ………….. , the ………….. is the inclined plane. But we have to bear a …………. weight.
Answer:
slope, shorter, greater

Question 5.
A screw is like a rolled up inclined plane made of an ………….. strip.
Answer:
iron

Question 6.
A wedge is used for ………… an object into two pieces or to ………….. the objects stuck together.
Answer:
breaking, separate

Question 7.
A farmer uses a strong …………. to remove the big stone bogged down in the farm.
Answer:
crow-bar

Question 8.
A device with a grooved wheel and thread designed to lift weights is called a …………. .
Answer:
pulley

Question 9.
When we use a pulley, force is applied in the downward direction for lifting the weight in an …………. direction.
Answer:
upward

Question 10.
Combination of an axle and a wheel is a …………. machine.
Answer:
simple

Question 11.
A needle and a nail are also kind of …………. .
Answer:
wedge

Question 12.
Machines are covered when not in use to prevent …………. settling on them.
Answer:
dust

Question 13.
In Archimedes’ screw, the pipe was placed at an angle of …………. with one end inside the …………. and the rod resting on a …………. .
Answer:
45°, water, flat surface.

Match the columns:

Question 1.

Column ‘A’	Column ‘B’
1. Pair of Scissors	a. Third order of lever
2. Tongs	b. Second order of lever
3. Opener	c. First order of lever

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Answer:

Column ‘A’	Column ‘B’
1. Pair of Scissors	c. First order of lever
2. Tongs	a. Third order of lever
3. Opener	b. Second order of lever

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Question 2.

Column ‘A’	Column ‘B’
1. Inclined plane	a. Needle
2. Pulley	b. Screw
3. Wedge	c. Crane

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Answer:

Column ‘A’	Column ‘B’
1. Inclined plane	b. Screw
2. Pulley	c. Crane
3. Wedge	a. Needle

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State whether the following statements are ‘true’ or ‘false’.

Question 1.
Lever helps big vehicle to climb up and down the mountain easily.
Answer:
False

Question 2.
Combination of wheel and axle is a simple machine.
Answer:
True

Question 3.
In pulley, force can be applied in upward direction.
Answer:
False

Question 4.
Screw is an example of wedge.
Answer:
False

Question 5.
In Archimedes screw, the rod rests on flat surface.
Answer:
True

Question 6.
A slanting plank is used to lift a weight.
Answer:
True

Question 7.
A winding road or ghat is an example of lever of first order.
Answer:
False

Answer the following questions in one sentence.

Question 1.
What is a machine?
Answer:
Devices which are used to get more work done in less time and less effort are called machines.

Question 2.
What is a simple machine?
Answer:
Machines which have only one or two parts and a simple and easy structure are called simple machines.

Question 3.
What is a complex machine?
Answer:
Some machines have many parts and they carry out many processes for completing a task. For this purpose, the parts are joined to each other. They are called complex machines.

Question 4.
List the properties of simple machines.
Answer:
Properties of simple machine are:

Question 5.
List properties of complex machines.
Answer:
Properties of complex machine are:

Question 6.
What is an inclined plane?
Answer:
A slanting plank which is used to lift a weight on which we bear less weight and lifting becomes easier is an inclined plane.

Question 7.
What is a screw?
Answer:
A screw is like a rolled up inclined plane made up of iron strip.

Question 8.
What is a wedge?
Answer:
A wedge is used for breaking an object into two pieces or to separate objects stuck together.

Question 9.
State examples of wedges.
Answer:
An axle, a knife, a chisel, a needle and a nail are different kinds of wedges.

Question 10.
What is a lever?
Answer:
A lever is a machine made up of 3 parts: effort, load and fulcrum.

Question 11.
What is a fulcrum?
Answer:
The support at which the rod of a lever is rested is called fulcrum of a lever. The lever rotates about the fulcrum.

Question 12.
What is a load?
Answer:
The weight lifted by a lever or the force against which the lever acts is called a load.

Question 13.
What is a load arm?
Answer:
The arm of the lever from the fulcrum to the load is called a load arm.

Question 14.
What is an effort?
Answer:
The force applied on the other end of the rod to lift the load is called an effort.

Question 15.
What is an effort arm?
Answer:
The part of the lever from the fulcrum to the effort is called an effort arm.

Question 16.
What is lever of the first order?
Answer:
The fulcrum is in the centre, the load is at one end while effort is at other end.

Question 17.
What is lever of the second order?
Answer:
The load is in the centre, the fulcrum on one side, and the effort on the other side.

Question 18.
What is lever of the third order?
Answer:
The effort is in the centre, the fulcrum on one side, and the load on the other side.

Question 19.
What is a pulley?
Answer:
A pulley is a device with a grooved wheel and thread designed to lift weights.

Question 2.
How does a pulley help us?
Answer:
If we use a pulley, force can be applied in the downward direction for lifting the weight in an upward direction. It is convenient and easy.

Give scientific reasons:

Question 1.
We use many simple machines in our day-to-day life.
Answer:
Simple machines can be handled easily and there are less chances of these machines breaking down or getting damaged. Hence, we use many simple machines in our day-to-day life.

Question 2.
Less force is required to fit a screw than to hammer a nail.
Answer:

Question 3.
Big vehicles easily climb up and down the mountains than a pathway.
Answer:
A winding road or ghat that goes up a mountain is like an inclined plane wrapped around the mountain. It helps big vehicles to climb, up and down the mountain easily.

Question 4.
Oil or lubricant is released between parts of machine.
Answer:
Oil or lubricant is released between parts that rub against each other so that there is less friction between them and wearing is reduced.

Question 5.
Machines are covered when not in use.
Answer:
Machines are covered when not in use to prevent dust settling on them.

Question 6.
How are machines protected from the effect of weather?
Answer:
To prevent the effect of weather, metallic parts in a machine are painted externally and the machines are always kept dry.

Draw the neat and labelled diagram of following:

Question 1.
The screw as an inclined plane.
Answer:

Question 2.
Archimedes’ screw
Answer:

Observe the following diagram and identify the order of lever.

Question 1.
Removing the lid.
Answer:

Question 2.
Picking up an object.
Answer:

Question 3.
Lifting a paper weight.

Answer:

Answer each of the question in brief:

Question 1.
With the help of the diagram explain lever of the 1st, 2nd, 3rd order.
Answer:
1. Lever of the First order: The fulcrum is in the centre, the load is at one end, while the effort is at the other end. e.g. scissors

2. Lever of the Second order: The load is in the centre, the fulcrum on one side, and the effort on the other side. e.g. lid opener

3. Lever of the Third order: The effort is in the centre, the fulcrum on one side, and the load on the other side. e.g. Tongs

Question 2.
How can machines be maintained?
Answer:

Question 3.
What is an inclined plane? Explain longer and shorter inclined plane.
Answer:

Question 6.
Explain the working of a giant wheel.
Answer:

Observe and discuss:

Question 1.
Name the devices and discuss how they help.

Answer:

Can you tell?

Question 1.
Observe the machines shown in the following pictures. For what purposes are they used? Can you name some other machines of this kind?

Answer:

Question 2.
Compare the pathway and a road, available to climb the mountain, the time and strength and your convenience, required to reach the mountain top.
Answer:
We can reach the mountain top by climbing the pathway early than by the road. The time required is less but the strength required is more. The road is easy to walk and more time consuming.

Question 3.
If the point of a needle or the edge of a knife become blunt, then the needle does not penetrate the cloth and the knife does not cut into the fruit. Why is this so?
Answer:
The tip of the needle or the edge of a knife becomes blunt due to regular use. Both the knife and the needle lose their sharpness.

Use your brain power!

Question 1.
Which task can be done using a lever?
Answer:
Task such as using a nut cracker, cutting paper with scissors, can be done using a lever.

Question 2.
Some machines we use in our day to day life are shown in picture. What is the type in each of these?

Answer:

Question 3.
When the pedal of the bicycle is rotating, the wheel starts rotating. How does this happen?
Answer:
Pedals of the bicycle are connected to the wheels through the axle, when the axle starts rotating, the wheels also start rotating.

Question 4.
Examples of pulley.
Answer:

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