Maharashtra Board Class 6 Science Solution Chapter 12 – Simple Machines
Balbharati Maharashtra Board Class 6 Science Solution Chapter 12: Simple Machines. Marathi or English Medium Students of Class 6 get here Simple Machines full Exercise Solution.
|Maharashtra Class 6|
1.) Classify the following as a lever , a pulley and an inclined plane :
- A wedge :an inclined plane
- a needle :an inclined plane
- a staircase :an inclined plane
- a slide : an inclined plane
- the wheel of a flagpole :a pulley
- nutcrackers :a lever
- scissors :a lever
- an opener : a lever
- an axe : an inclined plane
- a crane :a pulley
- a knife :an inclined plane
2.) Fill in the blanks using the proper word and complete the statements.
a.) The fulcrum in the centre , the load on one side and the effort on the other side make a lever of the first order.
b) The load in the centre, the fulcrum on one side and the effort on the other side make a lever of the second order.
c.) The effort in the centre, the load on one side and thefulcrum on the other side make a liver of the third order.
3.) Which machines will you use to do the following work? Write their types.
a.) To remove the lid of a tin.
A can opener should be used in order to remove the lid of a tin.
A can opener falls under the category of second class lever.
Second order lever refers to the one in which there is a load in the middle of the fulcrum and effort.
b.) To lift bricks to the top of a tall building.
A crane should be used in order to lift bricks to the top of a tall building.
A crane falls under the category of pulley.
Pulley is a device which consists of a grooved wheel and thread, and which are mainly designed for the purpose of lifting weights.
c.) To cut vegetables.
A knife should be used in order to cut vegetables.
A knife falls under the category of wedge.
An axe is used for the purpose of chopping wood. An axe is a sharp- edged tool which is created by connecting two inclined planes.
d.) To draw water from a well.
Wheel -axle should be used in order to draw water from a well.
Wheel- axle falls under the category of pulley.
Pulley is a device which comprises of a grooved wheel and thread ,and which are primarily devised for the purpose of lifting weights.
e.) To hold a papad for roasting it.
A pair of tongs should be used in order to hold a papad for roasting it.
A pair of tongs falls under the category of third order lever.
Third order lever is the one in which there is an effort in the middle of the fulcrum and load.
4.) Write the answers to the following questions in your own words.
a.) What is meant by simple machines?
Simple machines is the one which consists of only one or two parts and they does not have any complex structure. Such machines are very easy to handle and these machines are hardly subjected to breakage or any kind of damage. Such machines are quite useful in our day- to- day life activities. The nail cutter and bottle opener are some of the examples of simple machines.
b.) Mention the advantages of using a machine.
The advantages of using a machine are as follows:
i.) More work can be accomplished in less period of time with greater level of efficiency.
ii.) It requires less effort to achieve the desired task.
iii.) In order to enhance the task productivity, machines are used in both domestic and industrial purposes.
iv.) The usage of machines enables the factories to generate more in order to fulfill the market demands.
c.) What is meant by complex machines?
Complex machines are composed of several parts which executes several processes for the purpose of accomplishing a task. In order to achieve this purpose, the parts are linked to each other. Complex machine is composed of two or more simple machines. Complex machines have complicated structures. Complex machines are used in our everyday life purposes depending upon the extent of task that is to be performed and effort and time that is needed to attain it. Mixer grinder and sewing machines are some of the examples of complex machines.
d.) What is a lever? How are the orders of the lever determined?
A lever constitutes a simple machine which is composed of a fixed rod that possesses the capability of revolving around a pivot which is known as a fulcrum . Effort, load and fulcrum are the three different parts of a lever.
1.) Fulcrum – Fulcrum is the support point where the rod of a lever rests and this is known as fulcrum. The lever revolves around the fulcrum.
2.) Load –The capacity of the lever to lift the weight is known as load.
3.) Effort –The force exerted on the other edge of the rod in order to lift the load is known as effort.
The sequence of the liver are determined in accordance with the positions of the effort, the fulcrum and the load. Lever of the first order, lever of the second order and lever of the third order are the three different types of levers.
In first order lever, the fulcrum is in the middle position of the load and effort. Scissor is one of the relevant example of first class lever.
In second order lever, the load is in the central position of the fulcrum and effort. Nail clippers and nutcracker are some of the examples of second class lever.
In third order lever, the effort is in the centre position of the fulcrum and load . Cricket bats and fishing rod are some of the perfect examples of third class lever.
5.) Why is this so?
a.) Traveller’s bags have wheels.
Traveller’s bags have wheels because wheel constitutes a simple machine which enables to carry the bag very easily. There is decreased friction between the ground and the wheel, which facilitates to drag the bag comfortably without putting great effort. Therefore, less time and energy is required to carry the traveller’s bag.
b.) Machines have to be maintained.
A machine is made up of several parts. When they are in use, the parts of the machines rub against one another. For this reason, there is wearing out of these parts with the ongoing time period. Soil and dust leads to more friction, which subsequently worsens their condition. Some parts , also rust and erode due to the impact of the weather. Due to such wear and tear , the machines get’s damaged or turns worthless. In order to avert this condition, it is extremely essential to maintain the machines. All the parts of the machines are thoroughly cleaned during the time of maintenance. In order to reduce the friction that takes place between the parts of the machines, oil is released, which ultimately helps in reducing the wear out. Machines which are not in use are always covered, so that the dust does not settle on them. Metallic parts in a machine are painted externally, for the purpose of preventing the impact of weather and the machines should always be retained in a dry condition. Therefore, machines should always be maintained at regular intervals for the purpose of assuring their effective functioning.
c.) A bicycle is said to be a complex machine.
A bicycle is said to be a complex machine because it is composed of two or more simple machines, as for instance, wheel , handle , puddles and screw which executes several different tasks and contributes to its functioning in a collective manner. For this reason, bicycle is categorized as a complex machine.
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 see- 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 put small pieces of ice in the glass with the help of the tongs.
1.) See- saw
Sea -saw of falls under the category of first order level.
In first order level , the fulcrum is located in the middle of the load and effort.
Wheelbarrow falls under the category of second class lever.
Second class lever is the one in which the load is situated in the central position of the fulcrum and effort.
3.) Lemon squeezer
Lemon squeezer falls under the category of second order lever.
In second order lever, the load is situated at the middle of effort and fulcrum.