YADNYA e-Learning
Science Studies - 6th Standard
12. Simple Machines
Question And Answer
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.
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 fulcrum on one side and the load on the other side make a lever 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.
Ans: Machine: Can opener
Type: Inclined plane
(b) To lift bricks to the top of a tall building.
Ans: Machine: Wheel and the rope
Type: Pulley
(c) To cut vegetables.
Ans: Machine: Knife
Type: Wedge
(d) To draw water from a well.
Ans: Machine: wheel and rope
Type: Pulley
(e) To hold a papad for roasting it.
Ans: Machine: Pair of tongs
Type: Lever
4. Write the answers to the following questions in your own words.
(a) What is meant by simple machines ?
Ans: The machines which have only one or two parts and a simple and easy structure such machines are called simple machines.
Ex. The nail cutter, the bottle opener
(b) Mention the advantages of using a machine.
Ans: Advantages of using machine are as fallows:1) Machines are used for reducing efforts.
2) They save our time and do more work in less time.
(c) What is meant by complex Machines ?
Ans: The machines which have many parts and carry out many processes for completing a task and their parts are joined to one another. Therefore, these machines are called complex machines. E.g sewing machine, mixer
(d) What is a lever ? How are the orders of the lever
determined ?
Ans: A lever is simple machine. It has three components i.e fulcrum, load and effort order of lever is determinant on the
basis of the efforts, the fulcrum and the load.
1) Lever of the first order: The fulcrum is in the centre, load at one end and effort at other end.
2) Lever of second order: The load is in the centre, the fulcrum on one side and effort on other side.
3) Lever of the third order: The effort is in the centre, the fulcrum on one side and the load on other side.
5. Why is this so ?
(a) Traveller’s bags have wheels.
Ans: Traveller’s bags have wheels just because of easy movement of bags from one place to another. It convenient and easy to lift bag from one end to other in upward direction.
(b) Machines have to be maintained.
Ans: Parts of machine rub against one another when they are used. Soiled, dusty part create more friction some parts, affected by the weather, rust and erode. Machines get damage or become useless due to such wear and tear. To avoid this, it is necessary to maintain and take care of machines.
(c) A bicyle is said to be a complex machine.
Ans: A bicycle is a complex machine because its parts are joined to one another. The structure is complicate. Hence a bicycle is said to be 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 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.
Ans:
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