Question Answers For All Chapters – General Science Class 6
Simple Machines
Exercise
1. Classify the following as a lever, a pulley, or an inclined plane:
Answer –
A wedge – Inclined Plane
A needle – Inclined Plane
A staircase – Inclined Plane
A slide – Inclined Plane
The wheel of a flagpole – Pulley
Nutcrackers – Lever
Scissors – Lever
An opener – Lever
An axe – Inclined Plane
A crane – Pulley
A knife – Inclined Plane
2. Fill in the blanks using the proper word and complete the statements:
Answer –
(a) The fulcrum is in the center, the load on one side, and the effort on the other side make a lever of the first order.
(b) The load is in the center, the fulcrum on one side, and the effort on the other side make a lever of the second order.
(c) The effort is in the center, 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.
Answer –
(a) To remove the lid of a tin – Opener (Lever)
(b) To lift bricks to the top of a tall building – Crane (Pulley)
(c) To cut vegetables – Knife (Inclined Plane or Wedge)
(d) To draw water from a well – Pulley
(e) To hold a papad for roasting it – Tongs (Lever)
4. Write the answers to the following questions in your own words.
(a) What is meant by simple machines?
Answer – Simple machines are tools with few or no moving parts that make work easier. Examples include levers, pulleys, and inclined planes.
(b) Mention the advantages of using a machine.
Answer – Machines help us do work with less effort.
They save time and energy.
They make tasks easier and safer.
(c) What is meant by complex machines?
Answer – Complex machines are made up of multiple simple machines working together. Examples include bicycles and cranes.
(d) What is a lever? How are the orders of the lever determined?
Answer – A lever is a simple machine consisting of a bar that pivots on a fulcrum to lift or move loads. The order of the lever is determined by the positions of the fulcrum, load, and effort:
First order: Fulcrum in the center.
Second order: Load in the center.
Third order: Effort in the center.
5. Why is this so?
(a) Traveller’s bags have wheels.
Answer – Wheels make it easier to pull the bag by reducing friction.
(b) Machines have to be maintained.
Answer – Maintenance prevents wear and tear, so machines last longer and work properly.
(c) A bicycle is said to be a complex machine.
Answer – A bicycle has multiple simple machines like wheels, axles, levers, and pulleys working together.
6. Name the levers mentioned in the passage. Identify the fulcrum, load, and effort of each and say which type of lever it is.
Answer –
Seesaw:
Fulcrum: The middle support.
Load: The person sitting.
Effort: The force applied to move.
Type: First-order lever.
Wheelbarrow:
Fulcrum: The wheel.
Load: The leaves and garbage.
Effort: The person lifting it.
Type: Second-order lever.
Lemon Squeezer:
Fulcrum: The hinge of the squeezer.
Load: The lemon.
Effort: The force applied by hand.
Type: Second-order lever.
Tongs:
Fulcrum: The joint where the tongs are connected.
Load: The object being picked up.
Effort: The force applied by fingers.
Type: Third-order lever.
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