Here are the solutions to back lesson questions, enjoy !
a. What do you understand by the term machine?
Machine is a tool to make our work easier by helping us to overcome a larger force by applying less force.
b. Name the common simple machines.
The common simple machines are -
a) Inclined place
b) Wheel and axle
c) Wedge
d) Levers
e) Screw
h) Pulley
c. What are levers? Describe the types of levers with diagrams.
Lever is a simple machine to lift weight.
Diagram
d. What do you mean by pulley?
The pulley is a simple wheel which has a groove around the outside edges.
e. How is a wedge different from an inclined plane?
If two include planes are put together to form a sharp edge, it is called wedge. Hence, the wedge is a double inclined plane. It works on the principle of inclined planes. Example - Knives, axes and chisels.
f. Give some examples where inclined planes are used?
The inclined plane helps to move objects up to a height. Inclined planes can also be used to slow things down to stop. The examples of inclined planes are - steps, ski jump and wheelchair ramp.
g. What kind of machine is a steering wheel?
Steering wheel is a kind of wheel and axle machine.
h. Describe the principle of working of a screw.
The screw works on the principle of inclined plane. A screw is a rod or nail with grooves on its curved surface.Due to the presence of grooves the screw holds the wood more firmly than nails. Also, less force is required to insert into wood than nail because of the inclined edge.
i. Explain the working of a pulley.
The pulley is simply a wheel, which has a groove around the outside edge.
When an effort is applied to one end of the rope in a pulley or when you pull the rope - the load, which is the heavy object on the other end, is lifted off the ground. It is easier to lift by pulling down on the rope as gravity is on your side now.
j. What type of a lever is a fishing rod? Draw a diagram to show the lever.
Fishing rod is a type of Class 3 Lever where the load moves in the same direction as effort.
